Powerbook Motion Sensor
Anther url with some really cool info.
http://www.kernelthread.com/software/ams/
Basically, the new powerbooks released in 2005, include a system that can detect if the powerbook gets dropped and automatically parks the hard drive head to stop it getting damaged. Anyway, it seems that you can get the angles and motion detection information programatically!
What this means is that its possible to write programs that respond to physically moving the powerbook. i.e. tilt it to the right to skip to the next song in itunes, control windows so the top is always at the top no matter how you tilt the powerbook, etc etc etc
Someone has already written a small game that is tilt controlled:
http://www.balooba.se/baloobasoftware/index.html
I think this is way cool, so many possibilities
I think ill have a play when my new powerbook arrives