Examples of an actor playing two characters who are polar opposites.

Does anyone have any examples of two characters, played by the same actor, who are completely different from each other?

The only one I can really think of at the minute is Ethan Suplee. Plays a violent skinhead racist in American History X. Then in Remember the Titans, he is the completely opposite. He's the only white player on the team who doesn't start the movie by being racists against the black players.

I'd love to hear some other examples.