Blender is the premiere open source 3d animation program. It began as a in house animation program for the dutch gaming company NaN but late was brought and released as open source when the company went bankrupt. Since this time, Blender transformed from a primarily hobbist tool to a program that regularly pushes the frontier of 3d animation and is used as part of the production pipeline in many commercial studios.
The Blender Institute, based in Amsterdam, has also independently produced a couple of short HD 3d animations and a video game. These productions were funded by the Blender community and helped to advice the program itself. The most recent is called “Big Buck Bunny.” The youtube version is here and higher quality versions here. The game version is available here, http://www.yofrankie.org/