Alrighty. Here's what I've been able to come up with in a month's time. SUPER Bourtange! (not to be confused with Schell's "Bourtange") The source is here: http://github.com/lostandsupine/super-bourtange
I wrote it in clisp, on a netbook running windows, using cl-opengl. I had a really fun time making this. Seems like most of my lisp projects never get finished, so it's nice to have an external deadline to keep me on track.
It's a very asteroidsy space defense game. Asteroids fall down, and you have to shoot them. You've got guns, missiles that follow a parabolic path, and a whole menu full of upgrades.
This was my first experience with collision-detection, and rather than do any research I just made my own from scratch. It doesn't seem very efficient, but it works on a small scale game such as this.
Anyway, thanks to the hosts of ILGE 2010, and thanks to Schell for telling me that this was going on in the first place! -aaron