The new PowerBooks apparently have a small device called an accelerometer which is supposed to sense when the laptop is dropped. If sudden movement is detected by the accelerometer, the hard drive instantly parks its heads to protect data. Definitely a neat piece of technology, and, of course, it has piqued the interest of friendly hackers.
One guy has created a program that rotates windows on the screen as the laptop is tilted, while another has written a hack that moves to the previous or next track in iTunes when the laptop is tilted.
[ via chris2x.com ]