A 100% free multiplayer and single player strategic first person shooter with Command and Conquer 3: Tiberium Wars elements created in the Renegade Engine with TT 4.0 Code and Enhanced Graphics.
TCW is a complete total conversion for Renegade. Whilst it has the familiar cnc mode where you try to destroy the enemy base, it has coop missions and domination mode where you capture points to push back the enemy team.
As it's using W3D (the engine Renegade uses), you can also easily run it on any old hardware. The developers are very active (I've played with them!) and the regulars are friendly.
It's released but the developers are still adding new content. Definitely worth a look, it's fun multiplayer without bad game mechanics.