10. Ben Affleck & Matt Damon In Jay and Silent Bob Strike Back
Jay and Silent Bob Strike Back is another movie packed with cameos, but this double-header stands out the most. It occurs when Jay and Silent Bob, wandering around a film studio, end up on the set of Good Will Hunting 2: Hunting season, and stumble across the stars and writers of the original. While the "movie within a movie" scene is funny on its own, it is the grotesque versions of themselves that Affleck and Damon play that is the icing to the cake. They come off as huge a-holes; cursing at the production assistant and saying "Think about the paycheck" right before filming the scene. 9. Dan Marino In Ace Ventura: Pet Detective
1994's Ace Ventura: Pet Detective helped launch the film career of Jim Carrey, but it also did the same for Dan Marino (although his film career wasn't nearly as prolific as Carrey's subsequently became). In Ace Ventura, Marino and the Dolphins mascot, Snowflake, are kidnapped by a vengeful Ray Finkle (disguised as Lt Einhorn), former Dolphins kicker who missed a game winning field goal and blamed it on Marino for leaving the laces out. While the plot somewhat revolves around him, Marino doesn't have too much to do until the end of the film where he essentially redeems Ace by spotting Lt. Einhorn's bulging secret and revealing her to be a former man. His acting might not be impeccable exactly, but it's a key performance to say the least.