You know, I could probably replicate the physics I was making myself using Processing in no time... Maybe I'll give this a shot! I've seen some fantastic things made with it.
With that I refer you to the older games at the bottom of this page:
http://www.mattmakesgames.com/The "Jumper" series is made with Game Maker and so is Dim, and I think also An Untitled Story, I'm not sure about the others. I really liked the Jumper games (nice and challenging xD) so check out those or at the very least play the third one if you've got windows.
EDIT: And RunMan! That works on Mac too. Runman is fantastic.
EDIT 2:
WHAT AM I SUPPOSE TO DO? -__-