0.09 is the first "official" release. It's a very playable demo of the first five levels.
It would be 0.1 except that some art is missing -- level 4 and level 5 are missing backgrounds in some places.
Be aware that it's pretty hard to compile right now; it relies on ODE 0.7 and pyode from svn.
bouncy-0.09.tar.gz -- src tarball
bouncy-0.09-exe.zip -- py2exe'd Windows executable