1. Chilltown Becomes the First Big Brother Alliance
In Season 2, Big Brother legend Will Kirby formed the first of the show's many alliances, teaming up with Mike "Boogie" Malin to create Chilltown. Will eventually won that season after masterfully manipulating his fellow houseguests. The pair resuscitated Chilltown for the All-Star season in 2006 which was won by Mike Boogie, making Chilltown the most successful alliance in reality television history.
2. Marcellas Wins the Veto but Doesn't Use It
The Power of Veto allows a Big Brother contestant who has been nominated for eviction to remove his nomination, forcing the Head of Household to nominate someone else in his place. At the final five in Big Brother 3, Marcellas Reynolds won the Veto but chose not to use it on himself, believing he was safe no matter what happened. He was very wrong. After a tie vote he was evicted by Jason, the current Head of Household.
3. The Twin Twist
Big Brother throws twists into every season, and in Season 5 there was one in particular that amazed viewers. Twin sisters Adria and Natalie Montgomery played the first half of the game as one person (using Adria's name), switching places every couple of days. They were promised that they could both play as individuals if they lasted through the first five weeks, which they accomplished. Natalie was introduced into the game on day 35, though she had already spent plenty of time in the house. The season was aptly nicknamed "Project DNA," for "Do Not Assume."
4. Kaysar Meets the Revolving Door
Big Brother 6 gave fans the chance to vote their favorite evicted houseguest back into the game for a second chance. Fans overwhelmingly chose Kaysar Ridha, who was part of the Sovereign Six alliance in a house that was deeply divided. Upon his return, Kaysar participated in an endurance Head of Household competition that lasted over 14 hours. He and Jennifer Vasquez were the last two standing and Kaysar stepped down after eliciting a promise that he would not be nominated or evicted that week. Jennifer went back on her promise and Kaysar left the house once again, the very week he had returned.
5. The Toothbrush Incident
Big Brother 2 contestant Shannon Dragoo was an addition to the Chilltown alliance, having struck up a romance of sorts with Will Kirby. When Head of Household Hardy Ames-Hill nominated Shannon and Will for eviction, Shannon decided to do a little house cleaning. She took Hardy's electric toothbrush and gave the toilet a good scrubbing with it. She was immediately called to the Diary Room where she was instructed to tell Hardy what she had done. She lied and told him she had dropped and broken the toothbrush.
6. Dick Versus Jen
Season 8 brought us one of the most memorable contestants ever in the form of Evel Dick Donato. He clashed with many of the houseguests but his feud with Jen Johnson carried on until Jen was evicted. The two hated each other, and their arguments continued to escalate. In addition to shouting insults at his nemesis, Dick poured a glass of iced tea over her head in one episode. This all culminated in Jen going a little crazy, destroying Dick's cigarettes by dumping them in a garbage bin and pouring bleach all over them.
7. Janelle's One-Liner
Janelle Pierzina was an instant fan favorite during Big Brother 6. A blonde bombshell, she was also very clever and played the game with an intensity that hadn't been seen before. Janelle won the Head of Household competition immediately following her friend Kaysar's second ouster. When she was handed the keys to her private room by the outgoing Head of Household Jennifer, she turned to her enemies in the house and yelled, "Bye bye bitches!"
8. Jeff Uses the Coup D'Etat
The Coup D'Etat was a special power earned by one houseguest, which gave him the capability to overthrow the Head of Household and replace the nominees (despite the fact that most of the houseguests couldn't pronounce it). During Big Brother 11, Jeff Schroeder became the first person to actually use this power. Though the resulting nominations and eviction helped Jeff's game a great deal, his power move started a downward spiral for Chima, who broke down and ended up breaking many of Big Brother's rules. Throwing her microphone into the hot tub became the final straw and she ended up being removed from the game.
9. Janelle and Erika Bust Chilltown
Season 7 of Big Brother was a All-Star season, where memorable houseguests returned to compete against one another. Chilltown members Will Kirby and Mike Malin teamed up with Janelle Pierzina and Erika Landin respectively, and called their strategy "Operation Double Date." The girls didn't like each other and relied on the boys to guide them through the game. This group made it to the final four and at that point Janelle and Erika finally started to compare notes. Realizing they had been played all along, Janelle cast the vote necessary to evict Will from the game. Erika threw the final HoH competition, leading to Mike Boogie evicting Janelle and winning the season.
10. Dan Hugs Jessie as America's Player
My last "top 10" moment is a sentimental favorite and not one that changed the game in any way, shape, or form. In Season 8, Eric Stein played the game as America's Player. This meant that fans voted on who he should vote for, align with, and even nominate should he become Head of Household. In Season 10, Dan Gheesling was given a temporary stint as America's Player earning extra cash each time he carried out one of the fans' requests. One of these was to hug Jessie Godderz, a bodybuilder, for ten seconds. Dan carried out this task much to the dismay of Jessie, whose facial expressions were absolutely priceless.