My husband and son spent a lot of time this weekend playing a really neat game called Crayon Physics so I thought I'd share it with you all. I remember seeing it mentioned on a GT discussion board, but didn't check it out. My husband told me about a guy at his work who told him about it and before you know it we had it on our computer. It starts out easy like most games and gets more difficult as you go. You use basic principles of physics to get a red ball (I think it is really Newton's apple) to hit a yellow star. There are barriers along the way and you use a crayon to draw ramps, levers, etc. to help you get to the star. I'm not much of a physical science person so I think I'm on the 7th or 8th task, but my son and husband are past the 38th one. We even laughed a bit when things didn't work....like the ball flying a different way or a shape falling down. I know it doesn't sound funny, but just try it to see what I mean. There is a free demo version at www.crayonphysics.com.