Nope, never been in one. If I were to be in on a reality show, it wouldn't be one where it's a one time thing and I become a nobody after it's done (i.e. Real World, Survivor, etc). If I'm signing away my life to the reality TV gods, then I better benefit from it in the end.
Oh, and I've concluded I would be the "boring one" that wouldn't film dates, relationships, family, real friendships, etc.