Art of Illusion

Art of Illusion is a free, open source 3D modelling and rendering studio. Many of its capabilities rival those found in commercial programs. Highlights include subdivision surface based modelling tools, skeleton based animation, and a graphical language for designing procedural textures and materials..
The current version is 2.8.1, released Jan. 3, 2010. This version is both stable and powerful enough to be used for serious, high end animation work.

Click here to download the program.