Here's a few shots of the Lego Carousel in action. I attempted to show the drive motor in action, as well as the crank shafts that move the horses up and down. Overall, it's pretty neat that they managed to take something inherently square like Lego and make it round.
It's a fairly easy build, and at 3,263 pieces, I know I've never built anything bigger. It took about 12 hours, and I suspect most of that time involved looking for pieces.