Crayon Physics is a great new game by Kloonigames. I gave it a test drive last night. The graphics are quite simple but that's all part of the fun. You have to get the little red ball to hit the star by drawing things on the screen to interact with it. Sometimes it's easy and sometimes it's devilishly difficult.
The guy who wrote this game, Petri, wrote it in seven days. He has improved it since - with more levels and a level editor. And the game is a winner, it has that rare quality of making you feel like a kid again, just what a game should do.
There is a certain sense of wonder at watching the things you draw on the screen come to life and act as they would in a physical world. It makes for addictive gameplay and you may even learn a bit about physics in the process.
I definitely recommend you checking the trial version out.