Quake 4 Beta Demo

A single-player mission and two multiplayer maps
Activision and id Software have released a playable demo of Quake IV, giving you the chance to try out the very popular sequel available in retail stores since this October. In Quake IV, you are Matthew Kane, an elite member of Rhino Squad and Earth's valiant invasion force. Fight alone, with your squad, and in hover tanks and mechanized walkers as you engage in a heroic mission into the heart of the Strogg war machine. But, in this epic war between worlds, the only way to defeat the Strogg is to become one of them. Battle through early missions as a deadly marine, then after your capture as a marine-turned-Strogg with enhanced abilities and the power to turn the tide of the war.
Update: Activision announced that the multiplayer portion of the demo doesn't work online at the moment. The final version of the demo will be released early next week.
Quake 4 Beta Demo (326.71MB)