Valve Corporation is making great effort to make Linux a gaming platform, recently Valve pushed Half Life 2, Half Life 2 : Episode 1, Half Life 2 : Episode 2, and Half Life 2 : The Loast coast to Linux.
Currently these games are available in beta. Beta tag will be removed after testing and solving some comman issues. If you want to install this games on Linux then fire your steam client now.
So now Linux users have every single player games from Half Life series natively available for Linux. Happy gaming!