Chuck Liddell
For two years, Liddell held onto the light heavyweight championship until finally surrendering the belt to old nemesis, Quinton "Rampage" Jackson in 2007. Over his next five fights, he won only once, leading to an almost definite retirement following an April 2009 defeat to Mauricio Rua. But during his reign as champion, Liddell helped usher in an era of mainstream popularity for mixed martial arts. His own celebrity led to branching out into other forms of entertainment, including appearances in movies and on television. In the feature world, he made cameos in "How High" (2001) and "Cradle 2 the Grave" (2003), while on the small screen he had a memorable guest turn on an episode of "Entourage" (HBO, 2004-11), in which he appeared as himself in a "Punk'd"-style prank to get Johnny Drama (Kevin Dillon) into the ring with him. After an episode of "Blade: The Series" (Spike TV, 2006) and voicing himself on "The Simpsons" (Fox, 1989-), Liddell was a surprise inclusion for the season nine cast of "Dancing With the Stars" (ABC, 2005-).