#10. Anthony Michael Hall: Weird Science
There are three main types of movie nerds. One is an academic stereotype who doesn't talk much. The second is a hilarious weirdo who would be totally popular if he wasn't in a movie script. In Weird Science, Anthony Michael Hall perfected the third: the nerd whose sexual frustration has driven him insane.
Hall performs in Weird Science like his captured family will be killed if he's not funny. He packs more manic desperation into his lines than a dry-humping seventh grader. He delivers lines in ways that would make Christopher Walken say, "What a strange WAY to deliver your lines."
To be fair, almost every casting decision in Weird Science is irreplaceable. Bill Paxton will never have a more perfect role than Chet, and even after 25 years of filmmaking, this is still Robert Downey Jr.'s greatest moment:
#9. Fred Willard: Best in Show
In Best in Show, Fred Willard plays the color commentator for the Mayflower Dog Show. In just a few lines, he creates a character stupid enough to be confused by everything, but clever enough to fuck with his broadcast partner. He asks inane questions about foreign dog accents, jokes about sex fetishes and you can never tell if the actor next to him, Jim Piddock, is caught off guard by Fred Willard or the character he's playing.
No one else has the ability to make intentionally unfunny jokes work like this. His comic delivery is so natural that I don't think he can prevent it. If Fred Willard was a doctor, it would take him 15 tries to convince you he wasn't kidding about your bone cancer.