Breakfast Club. It's a classic but still a great movie because of that whole stereotypical clique thing that goes on.
Completely off topic but yes it's a very good movie. Christopher Nolan is doing a great job of making the Batman Franchise into the dark creepy stories they're supposed to be, unlike those old Batman movies. Of course there's no way I could forget to mention Heath Ledger. He definitely gave the performance of his career.