9. Hugh Hefner
The Playboy founder and chief creative officer appears in season 5 as himself. And you just knew that Glenn Quagmire would be involved in some way, given their womanising ways. Hugh Hefner appeared in the episode "Airport '07" in which Peter almost wrecks Glenn's piloting career when he siphon's off jet fuel for his car, causing Quagmire to later crash land the plane he is flying. Out of work and down in the dumps, Guagmire later meets the men's magazine legend who provides him with all the encouragement he needs to get back on his feet.