Seems the Maker Faire really stirred the DIY crowd up this year. For instance, check out this cape made by Andrew Lau. He stitched LEDs all over a black cape then used a microcontroller to display messages and the like.
Doesn’t seem like it’d be too hard to whip one up yourself, though the microcontroller programming could get a little hairy. Remember to start small on your projects but keep thinking big!