http://www.udk.com/
The Unreal Development Kit, is now completely free for non-comercial
projects, allowing development of standalone games on the Unreal 3
engine.
List of features:
* Editing
* Rendering
* Animation
* Scripting
* Physics
* Lighting
* Cinematics
* Terrain
* Networking
* Shaders
* Audio
* Particle Effects
* Artificial Intelligence
* Distributed Computing
* Destructible Environments
* Bink Video
* SpeedTree
* FaceFX