Fantastic Contraption! I think a few people on here might've played a few years ago, now there's a FC 2 and 3. Here's number 2: http://www.sparkworkz.com/fc2/
Use physics and a variety of building materials to get the pink ball into the pink square. It's not always as easy as it sounds, there's obstacles and things falling out of other things and crazy layouts. My favorite level on the first game was when you had to make a slingshot-thing around one circle of land to fling the ball up into an un-connected second circle of land.