http://www.octaveengine.com/en/index.html
There's a little peice of software called OE-CAKE! that allows you to play around with the physics in a simple way (draw lines), and it's very CPU-intensive.
Download: http://www.octaveengine.com/casual/down ... or_Win.zip
Been toying around a bit, just made this completely useless odd "machine" 
, and it's still going:
[Blocked Image: http://pici.se/pictures/stUoUnQKO.jpg]
