Go to this website:
or google - 2dboy and then go to the games section once when you get to their website
...download and install this game called World of Goo. Demo is free. Quite a bit of levels for a free game. Good fun. The download and installation process takes less than five minutes.
Check it out. You wont regret it!
You can also get it for the Wii in WiiWare. Only 15 bucks. I bought it for my Wii. I had a blast.
The game is original and clever. Love the music. It's funny. Simple, but really fun. Challenging at times. Definitely worth checking out. It's amazing that it only took a couple of guys to make the game (maybe a total of four people to do everything).