Here's a free little physics game. Quote from the site:

Phun is free for non-commercial use. This means you can download it, copy it etc, just don't make money using it (don't sell it or use it for promotional puposes, but it's ok for you to use it at work while your boss isn't looking).




Download it here! -> http://www.acc.umu.se/~emilk/downloads.html

(Don't forget to check out the "help.txt" file in the Phun -folder)