Annually at the University of Pennsylvania the Mechatronics course does Robockey has a final project. The rules are simple, 3 student built and programmed robots per team, 2 halves, 1 minute each in a double elimination autonomous robobattle to the finish.
I just got back from this years event and it was a good deal of fun, though it made me wish I had a bot competing. Some metal in the game as it were.
You can check out the full website at www.robockey.com. For video, go here. It's still live streaming if you read this before 8pm EST.