From George Smart's Wiki
As I mention elsewhere, I don't really play games on the computer. I own a Playstation (the original one), and a few games for that, but nothing since then. I use my computer mainly for working on, word processing, the Internet, email, etc. I recently, however, got back into a few old games. These are listed below.
I would just like to mention that all of the games listed here are running under Wine. To quote the website, 'Wine is a translation layer (a program loader) capable of running Windows applications on Linux and other POSIX compatible operating systems.' The guys there do an excellent job. Definitely worth a checkout if you're into Linux/Computers.
I run Steam under Wine. It works perfectly once running, though startup is a little clunky. Plays Portal and HalfLife2 fine, which is the only reason I use it. The WineHQ website gives an excellent howto on getting steam working.
I shall add more to this list as and when I get into more games. As of now, there are only a few.