I'm rusty at everything now, but if you're getting to grips fucking about in java, here's the source code (and compiled working version) of a simple 2 player asteroids / space war style game I wrote when I was fucking about at uni instead of doing proper work. It's not anywhere near finished and I think there's a version with better collision detection and a working fps counter kicking about somewhere.
It's a bit over the top with inheritance, I think I had it planned that it would be easily expandable to add new stuff in, which it sort of is, although from having a quick glance at the source code it was half way through a rewrite separating the graphics bit and the game loop. Can't really remember.
Here you go anyway if you're interested...
http://download.yousendit.com/E650B4A827F62263It's probably not the greatest bit of code you'll ever see. I might have the very simple start of a platform game kicking about somewhere, that's more of just getting something on screen and jumping about though.
If you view the html page it should come up.