Big Buck Bunny is a short developed by The Blender Institute, which is part of the Blender Foundation, a non-profit organization which develops the Open Source 3D video application Blender.
From the site:
Big Buck Bunny tells the story of a giant rabbit with a heart bigger than himself. When one sunny day three rodents rudely harass him, something snaps… and the rabbit ain’t no bunny anymore! In the typical cartoon tradition he prepares the nasty rodents a comical revenge.
The short is fantastic, it’s totally in the Pixar vein and shows the power of Blender. The amazing thing is that the Blender Foundation has released all assets including the animation data, characters, and textures under a Creative Commons Attribution License. The developers created a ton of new software and features for Blender while developing the short, and made gigantic technical leaps from their previous effort “Elephant’s Dream.
The team made improvements in hair and fur rendering, the particle system, UV mapping, shading, the render pipeline, constraints, and skinning. Those improvements were then released to the public in Blender v. 2.46.
You can watch Big Buck Bunny on the projects’ web site.