Algodoo

The Pendulum is scripted in this one to keep it constantly swinging. Also, it comes down a little slower, just like in the movie.

Here's the link to the real part in the movie.

WARNING! This can be very disturbing to some people. But if you've seen Rambo and that doesn't bother you "at all", then this won't either.

http://www.youtube.com/watch?v=xvZ6Xf9_QFA