While Valve is still working on bringing out as many games as possible for the Steam platform on Linux (Ubuntu), they just released Counter-Strike: Source for the platform. Team Fortess2, Half-Life and Counter-Strike 1.6 already are available for Steam on Linux but with the addition of the nr.1 online FPS shooter Counter-Strike: Source we can see that Valve is clearly moving strong on bringing all of their titles to Linux, probably also because of their upcoming Steambox that will run on Linux.
Counter-Strike: Source was originally created back in 2004 on the very first Source engine used for Half-Life 2. The game still has one of the biggest online communities and players playing daily. Gamers that have already bought the game for Windows/Mac will automatically be able to play the game in Linux aswell. If you don’t own Counter-Strike: Source yet you can buy it for 19.99$ on Steam.