The MacBook Pro laptops have a motion-sensor in them, designed to prevent damage to the hard-drive when dropped. This has already been put to admirable use for Mac lightsabre fights (I can imagine the calls that would be put into tech repair from people renacting the Darth/Obi Wan fights).
Here's a much more work-friendly use. This bit of scripting uses the motion-sensor to change virtual desktops when the monitor is tapped. The video is just great and it looks so much easier than a cluster of key combos.