• On Day 1, the 16 HouseGuests entered the house and were paired with their soulmate chosen for them by Big Brother based on forms filled out by the HouseGuests during their audition process.
• The soulmates were Adam & Sheila, Alex & Amanda, Allison & Ryan, Chelsia & James, Jacob & Sharon, Jen & Parker, Joshuah & Neil, and Matt & Natalie. In particular, Adam and Sheila fail to get along immediately, with Sheila taking offense at Adam calling her "Ma."
• It was revealed that Jen & Ryan are a real-life couple outside the House, and Jacob & Sharon are an ex-couple.
• On Day 1, Jen & Parker became the first Power Couple and had to evict another couple within hours of the competition.
• On Day 4, Alex & Amanda became the first Head of Household couple.
• On Day 7, Allison & Ryan and Jen & Parker were nominated for eviction.
• On Day 9, Matt & Natalie won the Power of Veto and decided not to use it on Day 11.

• Power Couple: "Falling for You"; Each couple was hoisted over a bed: one was hooked on a zipline and helped their partner hang onto them. If the unattached partner fell off of the attached one the team was eliminated. Jen & Parker won the competition and $10,000 and had to evict a couple within hours after the competition.
• HoH: "Do You Know Your Partner?"; The 14 HouseGuests had to answer questions about their soulmates correctly in order to earn hearts, the couple scoring the most hearts wins Head of Household. With 9 hearts, Alex & Amanda were named the first Head of Household couple.
• PoV: "In Sickness and in Health"; One team member got onto one of four huge revolving hearts and put their finger on a panic button. The other partners spun the heart. Matt & Natalie were the first couple to spin their heart 300 revolutions without letting go on the panic button and won the competition.

Adam, Alex, Allison, Amanda, Chelsia, Jacob, James, Jen, Joshuah, Matt, Natalie, Neil, Parker, Ryan, Sharon and Sheila entered on Day 1. Sharon re-entered the House as Neil's replacement on Day 7.

Jacob & Sharon were evicted on Day 3. Neil left the House due to an urgent personal matter on Day 7. Jen & Parker were evicted by a vote of 3 to 1 on Day 14.

• On Day 14, Chelsia & James became the new Head of Household couple.
• On Day 15, Alex & Amanda and Matt & Natalie were nominated for eviction.
• On Day 16, Joshuah & Sharon won the Power of Veto competition and chose to keep the nominations the same on Day 18.
• On Day 16, Amanda & Allison were simultaneously hospitalized for a brief period of time. Allison had an allergic reaction, while Amanda, who is hypoglycemic, fainted from low blood sugar. Both returned to the House later that night.
• After the Power of Veto competition, the HouseGuests gathered around a jumbo digital ticker tape screen, to learn about Sen. John McCain's primary victories, Sen. Barack Obama overtaking Hillary Clinton in the primaries, and Britney Spears regaining custody of her two children. The HouseGuests also saw one final headline that read "The Hudson River virus is threatening those cut off from the outside world", in a reference to a new episode of the CBS series Jericho.

• HoH: "Big Brother Democracy"; On Day 14, the remaining couples were asked to guess how the majority would respond to six questions. The couple with the most points was crowned the new HoH couple. With six out of six correct, Chelsia & James were the named the second HoH couple.
• Food: "What A Catch!"; On Day 15 the House participated in the first food competition. The object of the competition was to fill the opposing team's nets with so much fish that the player had to drop his net. Team "Sea-duction", composed of Joshuah, Sharon, Ryan, Allison, Matt and Natalie; who won the competition. Team "Dev-ocean", composed of Adam, Sheila, James, Chelsia, Alex and Amanda; who lost the competition. James & Chelsia weren't put on the slop diet since they were HoH.
• PoV: "Communication Breakdown"; On Day 16, the couples playing had to find cables in a storage area packed among thousands of peanuts in barrels labeled "Jericho". They then had to get the correct sized cables to connect their four electrical poles to their individual generator. When done, team members must hit a red button on their generator. Joshuah & Sharon won the Power of Veto and the House was rewarded with information from the outside world.

Alex & Amanda were evicted by a unanimous vote on Day 21.

• On Day 21, Joshuah & Sharon became the next Head of Household couple.
• On Day 22, Allison & Ryan and Matt & Natalie were nominated for eviction.
• On Day 23, Matt & Natalie won the Power of Veto and chose to use the veto on themselves on Day 25. Joshuah & Sharon replaced Matt & Natalie with Sheila & Adam.
• On Day 24, the HouseGuests received a note from Big Brother about a siren that will sound in the coming weeks.
• On Day 28, after the first eviction vote was announced, Big Brother split the remaining couples into individuals for the remainder of the season.

• HoH: "Words of Love"; the competition was a quiz based on the love quotes around the House. HouseGuests were to buzz in when they thought they knew the correct author. The first HouseGuest to buzz in and answer correctly got to eliminate another HouseGuest from the competition. If a HouseGuest buzzed in and answered incorrectly was eliminated. The competition was played in two rounds broken up by gender. With both Joshuah and Sharon winning their rounds, they became the new Head of Household couple.
• Food: "Big Asparagus!"; the men must guess the weight of their partners and then gather enough asparagus to weigh the same amount. If they got within ten pounds of their partner's weight, the whole House got two major food groups. The House won: beverages & snacks, vegetables & fruits, and meats & cheeses; but failed to get carbs & a feast.
• PoV: "Cupid is as Cupid Does"; The couples had to figure out a picture puzzle. The women were strapped into a harness that moved them up into the air as the men ran across the yard to puzzle pieces. Each couple had more puzzle pieces than needed, the women had to figure out which pieces they needed while in the air. Upon completion of the puzzle, the men had to run back to retrieve Cupid's arrow, which the women had to plunge into their heart in the air to win. Matt & Natalie won the competition.

On Day 28, Allison & Ryan received two votes and was the next couple to be evicted from the House, but upon leaving the siren went off and the HouseGuests were informed that the couples were split up into individual players. The HouseGuests had to chose between Allison or Ryan to evict.

Allison was evicted by a unanimous vote on Day 28.

• On Day 28, Ryan became the first single Head of Household of the season.
• On Day 29, Ryan nominated Chelsia and Sharon for eviction.
• On Day 30, Chelsia won the Power of Veto, and chose to use it on herself on Day 32. Ryan nominated James in her place.

• HoH: "Time After Time"; Julie asks true/false questions on whether an event occurred in the house before or after another event.
• Food:"A Little 'Fon' Will 'Due' Ya!"; the House was separated into two teams. The blue team consisted of Adam, James, Matt and Natalie who were the "Won-due-fuls". And the red team named the "Fon-tastics" consisted of Chelsia, Joshuah, Sharon and Sheila. The object was to get into two pools of chocolate complete with fountains and slides while players one by one went down the slide into the pool to retrieve letters to spell out food items. For each food item correctly spelled and filled out on the team's shopping list, a point was awarded. The team with the most points won the food items they spelled out. With 12 food items spelled and filled out correctly; the blue team won the competition and had the food items listed for the week while the red team was put on slop.
• PoV: "Color of Veto"; the HouseGuests had to use an oversized pool stick to shoot their ball as close as possible to the Veto pocket, located at the center of an oversized pool table with a string of pockets carved in the center of an oversized pool table with a string of pockets carved in the center of the table. The eliminated HouseGuest from each round wins a prize, however a HouseGuest can keep their prize or chose a prize already won by another HouseGuest. Chelsie won the Power of Veto, Shelia won the red unitard from Big Brother 8, Sharon won a slop pass, Joshuah won letters from home, Adam won a motorcycle and Ryan won $10,000.

On Day 35, James was evicted from the Big Brother House with a 5-1 vote.

On Day 35, the HouseGuests had to decide to bring back James or an evicted HouseGuest that was in the "mystery box." The HouseGuests voted to bring back James in a 5-3 vote. Alex was voted by the viewing public to be the HouseGuest in the "mystery box."

• On Day 35, James became the Head of Household for the week.
• On Day 36, James nominated Ryan and Shelia for eviction.
• On Day 37, James won the Power of Veto, and chose to use it on Shelia on Day 39. James nominated Matt in her place.

• HoH: "Big Brother Disco"; the HouseGuests stood on gold discs attached to the tops of hanging disco balls and were spun around continuously while holding on with the chains used to attach the disco balls to the metal structure. An over-sized champagne bottle shot soap suds at the HouseGuests at various times during the competition. After four and a half hours, James outlasted Natalie and became the new Head of Household.
• PoV: "Trapped in the Cage"; players must walk along a series of balance beams to transfer 500 blocks from a cage to a tube. They could only move two blocks at a time, if they fell off the beam or dropped a block, they were eliminated. The first player to move all of their blocks won. With only James and Joshuah left, James successfully transferred all 500 blocks and won the Power of Veto.

On Day 42, Matt was evicted with a 4-3 vote. James, as Head of Household, had to cast the deciding vote. Matt became the first member of the Big Brother 9 jury.

• On Day 42, Adam became the Head of Household for the week.
• On Day 43, the HouseGuests played in a Luxury competition.
• On Day 43, Adam nominated Chelsia and James for eviction.
• On Day 44, James won the Power of Veto, and chose to use it on himself on Day 46. Adam nominated Sharon in his place.
• On Day 45, Chelsia won a $21,000 dollar VIP trip to Las Vegas before the screening of the film 21, in which her popcorn bucket had a golden ticket for the prize.

• HoH: "En Garde"; the HouseGuests faced off two at a time and had to guess which evicted HouseGuests made certain statements in the Diary Room. The player who buzzed in first and answered correctly stayed in the game, while their opponent was eliminated. The person who remained chose the next two HouseGuests to compete. With Adam and Chelsia facing off, Adam answered the last question quickly and correctly, winning his first Head of Household competition.
• Luxury: "Big Brother Blackjack"; the HouseGuests are dealt a series of cards. Each card has a different HouseGuest's face on it as well as a number. To win, HouseGuests must buzz in and list the cards that add up exactly to 21. Each correct answer earned them a chip. If answered incorrectly, they were eliminated. The winner got four movie passes to a screening of the Columbia Pictures film 21, the winner was allowed to select three other HouseGuests to join them. Ryan won the movie passes giving them to Adam, James and Natalie. He then was offered to risk the movie passes in order to play a round of traditional Blackjack for a chance to win a $21,000 dollar VIP trip to Las Vegas. Adam, as the dealer beat Ryan's two nines totaling 18 with Adam's three cards totaling 19. Ryan lost the prize package and the movie reward, which were then given to Chelsia, Joshuah, Sharon and Sheila.
• PoV: "Club Evel"; Big Brother 8 contestant "Evel Dick" Donato returned to the Big Brother House to host the PoV competition. The HouseGuests replayed a game from last season, where they had to drink concoctions to secure shots in a croquet game. The player who scored the most points in croquet won the Power of Veto. If the player scored more than Dick's score of 33 from last season, he or she would have also won a classic Gibson Les Paul guitar and amplifier. But if no one beat his score, Dick would get the guitar for himself. James drank 10 concoctions and scored 29 points, which won him the Power of Veto.

Chelsia was evicted from the Big Brother House on Day 49 by a unanimous 5-0 vote. She became the second jury member.

• On Day 49, Natalie became the Head of Household for the week..
• On Day 50, Natalie nominated James and Joshuah for eviction.
• On Day 51, James won the Power of Veto, and chose to use it on himself on Day 53. Natalie nominated Sharon in his place.

• HoH: "Big Brother Election"; viewers were asked to answer questions on CBS.com about each of the HouseGuests as if they were running for president. On an American flag-like game board, the HouseGuests were told to raise either their left or right hand to answer questions on how they thought viewers voted. For each correct answer, the HouseGuest moved one step. The player in the lead after seven questions would be the new Head of Household. With six out of seven answers correct, Natalie became the new Head of Household for the week.
• Food: "To Slop or Not to Slop"; HouseGuests must insert cards into their watermelon and choose either slop or food. The object of the competition is to figure out what the majority of the House decides and be in the minority group. If three or more HouseGuests choose their slop cards, then those people are on slop. But if three or more choose the food card, then they will be on slop and the people who chose the slop card will be on food. With Adam being the only one choosing the food card, he got food. James, Josh, Ryan, Sheila and Sharon all chose the slop card and were put on slop for the week.
• PoV: " "Big Brother Boardwalk"; players walk out to find objects from Big Brother past and present. The players had to guess how many objects made up a certain item by comparing it to a small version. After seeing each others answers, they had the option to play their number or fold. A player who folds can not get a point, but he or she also can not get eliminated from the game. The person who is closest to the correct answer got a point, while the person who is the farthest off was eliminated. The first player who got to three points won the Power of Veto. After Joshuah, Natalie and Sharon were eliminated; James, Ryan and Sheila were left. With James getting three consecutive answers correct, he won the Power of Veto.

On Day 56, Joshuah was evicted from the Big Brother House by a vote of 3-1. He became the third jury member.

• On Day 56, Adam became the new Head of Household.
• On Day 57, Adam nominated Sharon and Sheila for eviction.
• On Day 58, Ryan won the Power of Veto and chose to use it on Shelia on Day 60. Adam nominated James in her place.

• HoH: "More...or Less"; the HouseGuests were read statements about the number of things in the House, such as how many camera windows there are. The HouseGuests would then have to answer whether or not the actual number was more or less than the number given in the original statement. A HouseGuest who correctly identified whether or not the number was more or less would receive a point. The HouseGuest with the most points after seven questions would become the new Head of Household. After seven questions, Adam had the most points and became the new Head of Household.
• Food: "A True Big Brother Mash"; the HouseGuests have to make pathways down a ramp filled with pots and pans using only mashed potatoes, then pour gravy down the pathway into containers. Each container represented a food group or one of three luxury items: a feast, a grill or lawn toys. After 10 minutes, the HouseGuests won Meats & Fish, Desserts & Snacks, Dairy & Eggs, Bread & Pasta, and won a Grill and Lawn Toys.
• PoV: "The Rainmaker"; the HouseGuests walked into the backyard which was transformed into a parched desert landscape dominated by a huge stone god. The stone god revealed a past event in the Big Brother House, and the HouseGuests had to search the backyard for rocks with numbers on them and bring them back with the day the event happened. If only one person brought back the incorrect day, they were eliminated. If there were more than one incorrect answer, the person with the answer furthest from the correct number was eliminated. In the last round, Adam and Ryan remained. Ryan correctly got the number in first before Adam which won him his first Power of Veto.

• On Day 63, Sheila became the Head of Household.
• On Day 64, Sheila nominated Adam and Sharon for eviction. Big Brother alerted the HouseGuests that the Power of Veto competition would be held that night.
• On Day 65, Adam won the Power of Veto, and chose to use it on himself on Day 67. Sheila nominated Natalie in his place.
• On Day 66, Sheila celebrated her 46th birthday.

• HoH: "Glass Houses"; The HouseGuests go outside to the backyard and find four large plexi-glass boxes. The HouseGuests are told to grab on to either the bar or rope hanging in the box. If the HouseGuest fell out, they were eliminated. After 3 hours, Natalie got down from her box, giving Sheila her first Head of Household competition win.
• PoV: "PoTV"; One by one the HouseGuests go outside to find the back yard transformed into a big old-fashioned TV room, the big TV is made up of nine different screens, which each have a remote that controls them. When all nine screens are on the correct channels, a picture will be revealed. There are two puzzles, one of them with the HouseGuests' faces attached to Big Brother 8 contestant "Evel Dick" Donato's body, which is not complete, and the other one with  who sport hairstyles of all the HouseGuests. With the fastest time belonging to Adam with 3:20, he won the Power of Veto.

• On Day 70, Ryan became the Head of Household.
• On Day 71, Ryan nominated Sharon and Sheila for eviction.
• On Day 71, the HouseGuests played in teams for a luxury competition. Ryan and Sharon won the competition.
• On Day 72, Ryan won the Power of Veto and chose to leave the nominations the same.
• On Day 74, Big Brother alerted the HouseGuests that on Day 75, there would be an eviction.

• HoH: "Fact or Fiction"; Contestants were standing in a circle with privacy walls between them. Questions and statements referencing aspects of the game and the House up to that point were asked. Contestants stepped forward if they thought the statement was fact, and back if fiction. Ryan became the new Head of Household after answering the tie-breaker question correctly. This competition is considered controversial on account of the last statement.
• Luxury: "What Happens In Vegas..."; teams had to break prop bottles over each others heads. Only seven bottles had special dice rings. When a team found a dice ring, they had to put it on one of the nine squares on a playing board. Once all nine squares were filled, a wheel with nine corresponding boxes was spun. If the box on the wheel matched one of the boxes chosen by one of the teams, that team won the prize. The HouseGuests competed for the chance at an in-house screening of the 20th Century Fox film What Happens in Vegas..., a VIP experience that includes a shopping spree and tickets to the May 1 premiere of the film in Hollywood, and a chance to meet the cast at an after party. The losers were linked together for 24 hours. Ryan as HoH spun the wheel first and matched one of the boxes, winning Sharon and him the prize. The losers, Adam and Sheila, were linked together for 24 hours.
• PoV: "Big Brother Derby"; the yard was broken into quadrants, one for each of the HouseGuests. On each of their walls were five headless jockeys. They had to put the faces of the five evicted HouseGuests currently in the Jury House in order on the jockeys, and attach two cards to each of them that describe individual facts about their game. Once the HouseGuest has a face and two cards attached to the jockey, they rang their bell to find out if they can move on to the next jockey. If the buzzer rang, they have to go back. Ryan successfully completed all five jockeys first and won the final Power of Veto of the season.

• On Day 75, Ryan won the first part of the final Head of Household competition.
• On Day 76, Adam won the second part of the final Head of Household competition.
• On Day 77, Ryan won the final Head of Household competition, beating Adam.
• On Day 77, Sheila was evicted by Ryan, leaving Adam & Ryan in the final two.
• On Day 81, James was voted as America's Favorite Juror and was awarded $25,000. Sheila was runner-up in the America's Choice. It was announced on House Calls that Sharon came in third to win the prize.

• HoH, Pt. 1: "Up A Creek"; the final three remaining HouseGuests go outside and climb up onto a platform with running water. They attach themselves to boogie boards and grab onto a rope. The last person holding a rope won the first part of the final Head of Household. Ryan won the first part of the final Head of Household competition.

• HoH, Pt. 2: "Who's The Guinea Pig Now?"; Adam and Sheila competed in the second part of the Final Head of Household Competition. The competition involved a giant hamster wheel which rotated a large maze on the side of the wheel. The HouseGuests had to retrieve balls with the names of the previous Heads of Household in order. They then had to place the balls on a wall in the correct order. Alex & Amanda, James & Chelsia, and Joshuah & Sharon, as Head of Household Couples, were on one ball. Adam and Ryan each had two balls, as they held Head of Household twice. The correct order was: Alex & Amanda, James & Chelsia, Joshuah & Sharon, Ryan, James, Adam, Natalie, Adam, Sheila, and Ryan. Adam won the second part of the final HoH Competition.

• HoH, Pt. 3: "Jury Statements"; Ryan and Adam faced off in the final part of the HoH competition. They were asked to complete statements made by Matt, Chelsia, Joshuah, James, Natalie and Sharon. Ryan won the final Head of Household Competition by 3-2.