Saw District 9.
Go see it.
Action must with plenty of intense action, pretty freaking gorey, but the fact that the little weapons are capable of so much is part of what makes it so good. It also helps that the guys really deserve what comes to them, you can't help but smile!
Of course, then again I've been told I can have a sick sense of humor, what with Dark knight's Joker having me laugh hysterically with every one of his actions in the movie, specially the magic trick scene...