Here's an addictive game, fast paced and fun. Kind of like asteroids for the 31st century and it includes black holes (oooh...).
You'll have to find it with google on the internet (M$ sent them a threatening letter and they had to stop development). The latest version is 5.4 and needs to be run with wine. I ran it under FC6 with wine 0.9.35 from extras and it performed absolutely perfectly.