When I started with Linux I thought it would never be possible that we would see video games like for DOS under Linux.
Then came the port of Doom to Linux and I nearly could not believe it.
When I started with Linux on other architectures like Linux Sparc and Linux Alpha I thought it would never be possible that we would see those video games for them.
The game developers seem to have realised that many guys who like to play games also like to "play" Linux ;) And here we are now with sources to two great games, i.e. Doom and Descent, and binary versions for a third, i.e. Quake.
The following games are currently in my posession ;)