I thought it was worth mentioning since it's a good little puzzle/physics game.
World of Goo is having an anniversary sale and there's really no reason to not purchase it since you can get it for as little as a penny. That's if you're exceptionally cheap, but still, that's one penny that they probably wouldn't have gotten before.
http://2dboy.com/games.php
I wish I had a penny. ;-;
I want it for $0.00!