Mac Only: Have you ever wanted a car alarm for your Powerbook? Now you can have one.
When activated simply move the iBook/PowerBook away from the axis it was when it was activated, your iBook/PowerBook will now sound a alarm and flash your screen (Must enable in Universal Access preference pane)
You'll need a PowerBook or iBook (mid 2005 Model) with AMS or SMS enabled, Mac OS X 10.3 or later. Thanks to Dave for the tip and demonstration.