Since Apple first introduced the accelerometer in the late Powerbooks (intended as a safety feature), there’s been a persistant question of “how can we play with this?” floating in the heads of Mac fans and those of the techie persuasion.
This example, via Lifehacker, is by far the most obvious: a puzzler much in the same vein as Super Monkey Ball, where tilting the MacBook allows one to navigate the sphere around the maze. At the very least, it’s neat to watch, but from a practical standpoint, I imagine it would get tiresome very quickly (especially with the 17″ MacBook Pro; at 6.8 pounds, it’s an average-weight laptop, but an extremely heavy controller).