I just finished watching
Elephant. It was rather good. I find it more than a little creepy that the majority of the characters had their actors' names, though, and the last line was downright disturbing.
The cinematography was stunning. In one part, there were three runs through the same events, each of which was a continuous shot following a different character. Going back over it mentally, it would be easy to do in post-production, since I don't think any two of them show the same character voicing the same lines. Even knowing that, the effect is really cool.