For all your Free and Open Source Software needs.
Blender.org Before Maya, Houdini and all these other 3D apps jumped on the Python bandwagon there was Blender. This app gets more polished with each new release and their scripting reference section is definitely worth checking out.
Nodebox.net is a little known app that I came upon some while ago. It seems that it was developed by some grad students who wanted to have a Processing type of environment for quick Python prototyping.
Python CGI 