5. Jim Carrey - Eternal Sunshine Of The Spotless Mind (2004)
The Role: Carrey plays heartbroken Joel Barish, who decides to have his memory erased after discovering that his ex-girlfriend (Kate Winslet, who also gives an Oscar-deserving performance) has had the same procedure done. We watch Joel as he relives his memories to find that he's still in love with her.
Why It's Oscar Worthy: Forget films like Mr. Popper's Penguins, The Incredible Burt Wonderstone, or Fun with Dick and Jane, when he wants to be, Jim Carrey can be one of the finest actors in Hollywood. Carrey is funny, sympathetic, and keeps Joel likable throughout the film. Joel says some pretty horrible things, but Carrey's stellar performance keeps us on his side--even when we shouldn't be.