Monsters University.
I don't normally do the prequel/sequel/whatever-quel thing, but this was really rather good - whilst you don't have to have watched Monsters Inc., some of the jokes will make more sense if you have. Of course, since it's Pixar you've got drop-dead gorgeous animation, and since the Mouse is involved you've also got periods of anvilicious moralising. Even so, it's worth a watch.
I still prefer the original Monsters Inc. though (it's one of my all-time favourite movies)