If you're looking for something to stretch the old Java brain cells you might be interested in the Queue ICPC Challenge as mentioned on JavaLobby.
The programming challenge allows anyone to submit a player in a game called Capture. Capture is all about turning a field of grey pucks into your player's color (red or blue). This is done by using a sled that can move around and encircle a set of pucks. As long as one of your colored pucks is in the set, the grey pucks will change to your color. However, if the set also contains another player's colored puck then they all revert back to grey. Be careful to make sure one of your pucks is included because if the set contains an opponent's puck and not yours then you will convert all the grey pucks to their color. And, to make it more interesting each player has a couple of bumpers that can move the pucks around the board. There's an instructional video on the Queue ICPC Challenge website that explains it all visually.
The challenge is to write an automated player in Java (or C++ or C#) that captures more pucks than your opponent. There's a downloadable zip file with everything you need to create a player, including some sample players to test your player against. The deadline for submitting a player into the tournament is February 7 2010.