After wanting to put LEDs in everything, I drafted a pattern to make a faux fur scarf hoodie, complete with fleece-lined hoodie and pockets.
Initially, I ran a hand-soldered strand of slow change RGB LEDs off a 3xAA battery pack and held a large switch in place on the outside of the hoodie with a couple large washers.
Since the color changing scarf was such a hit with friends, I made some single color scarves as well. I used remnants of faux fur and made some smaller scarves for single color LEDs for some friends.
Since then, I've updated this piece a number of times.