This clothing mod just has dangerous written all over it, but then again it doesn't snow here so perhaps it is the life saver it seems to be. Using a 9v battery & some standard wire inserted throughout a jacket and you have an electrically heated jacket. Pretty simple, check out the project write-up for more info.
The picodore 64 is a commodore 64 based PDA. It has a full keyboard and most the standard I/O ports a computer should have. The write-up has a lot of pictures and further details if you're interested in building your own.
Another cool application of accelerometers is in this acceleration sensing glove. This project write-up comes from a student at Berkeley tasked with deciphering hand motions/gestures. The software & schematics are all right there waiting for you.
So when it's nearing your girlfriend's birthday, make sure to have this one bookmarked. The LED shirt uses an AVRmega16 microcontroller to control all the leds. One additional thing...try not to walk into an airport with one of these on, bad things might happen to you =P.