this gasme kicks ass i just started playing it agian for the first time in years.
duke nukem 3d
I haven't played Duke 3D in a while. http://icculus.org/ started porting it to Linux right after the Duke 3D source code was released, but I don't think they've gotten very far.
The Quake games on the other hand, I play all the time 😃 GL Quake and GL Quake II are sweet on Linux (I never played the GL versions when I was using Windows), and I just got the Quake III Team Arena expansion this summer, and am eager to try it out when I get home from my summer house.