Counter-Strike Source

Valve is offering a worldwide Team Fortress 2 Free Weekend that is going on now! You can join in and play the full game for free, including the new content just released in the TF2: Gold Rush Update. All you need is a Steam account to play. The Free Weekend is available to players all around the world and ends this Sunday, May 4, 2008 at 1pm PDT.

More Information:: Team Fortress 2 - Gold Rush Page