The most recent instalment in the Call of Duty franchise is notable — not because of the running around and blowing stuff up, that's dull — but because Kevin Spacey plays a genuine, multi-faceted character. He starts out nice, and ends up trying to destroy the world with poison gas whilst being a racist or something. This isn't new for Spacey.
He plays a virtually identical character in 21, one of my favorite movies. He swoops in on the protagonist when he's seemingly out of hope, offers him a new beginning, and then goes slightly psycho later on. 21's more than just a good Spacey performance, though: it's all-around one of the better films about gambling ever made. Best of all, it's based (loosely) on the real-life MIT Blackjack Team, so you can actually enjoy the down-on-his-luck college kid screwing over the establishment.
It's streaming on Netflix, or you can rent for a few bucks on the movie service of your choice.