Walaber has published a freeware game called "Walaber's Trampoline". What makes it interesting (besides having a totally original and crazy concept), is that most of the modeling was done with Blender and that he used the Ogre3D game engine.
Walaber writes on BlenderArtists.org:
Here are some images from my game "Walaber's Trampoline". All models except for the male gymnast were made by me in Blender. The Male gymnast model was made by another artist in Max, but I rigged and animated it in Blender. Lightmapping was done with Gile[s], the renderer is Ogre3D. The physics are using the Newton Dynamics engine.
As for the music, the game manual lists all of the artists, make sure to support them by visiting their websites, they were kind enough to let me use their music for free!
Check out the trailer, or download the full game (Windows only):