A Clockwork Orange
Before you see the movie, I'd definitely suggest reading the book A Clockwork Orange by Anthony Burgess. The book and movie are both worth spending a few hours of your life on, though be warned, they are both "ultra violent" and truly disturbing. The movie has value though, it's a fairly original look at how society deals with things that can cause it discomfort, both morally and immorally. The real magic of the movie is how Kubrick can create sympathy for a really despicable main character. Anyway, A Clockwork Orange is worth seeing, just don't bring your underage children.