I've also got Quake 3 Arena. We could also play OpenArena. http://www.openarena.ws/
Yep, OpenArena is another option. I only prefer Quake III because last time I played OpenArena it's graphics and weapons didn't seem really as fun to play.
I propose anyone who might be interested in a lower-spec gaming session joins IRC tonight at the same time as Wayne has already proposed, and we can thrash out which we want to play then, when we see who turns up and what they've got installed.
Peter.