Good, but needs work
I love the joke that you used at the end - straight out of Malachy's BBS Signature ;)
Still, what we have here is a great concept, but it was really lacking in places and as a result, I marked it down. You cut corners with the animation - when Mr. Landis enters the room and double takes the fat kid that ate the cake. You ran this loop a few times over and it really ruined the effect for me, personally. The same could be said for the fact that the characters stopped lip-synch about a tenth of the way through the piece. If you're not going to lip-sync, then don't, but equally, don't do a whole piece, where they do some and not for the rest. If you're trying to say that they are thinking, have them look thoughtful - eyes towards the ceiling, stroke their chin, or something like that.
Perhaps, you would have had more of a reaction from the class, that looked a little wooden, as if you're just sitting them in the background for filler material - they wouldn't sit perfectly still in real life, so why have them do that here.
Finally, we come to the audio - it needs to be better quality - move slightly further from the mic an see what you can do. Failing that, go to the Audio Forum and search for the voice actors wanted thread, where you can get some specialists in for it.
You're getting there, but aren't quite home yet.
[Review Request Club]