talk about bad timing for reading a thread, i just threw out the color organ i built in electronics 12 class 2 weeks ago.... i had it in a box for 17 years then threw it out 2 weeks ago...

ah well. if you have a Car audio store in your area check that out, they have a TON of stuff that flashes to music. I don't know where you live, but if you have a decent sized China Town, you might check that out too, i have had good luck finding stuff like that here in Vancouver. all this stuff runs on 12v but it isn't hard to grab that in a cab. you computer or most game power supplies output 12v. all the malls around here have store dedicated to "pimping out" your Honda/Toyota again lots of little blinky lights.
last suggestion, if you have a "Spencer's gifts" in your area, check the back of the store... tons of stuff like that, go into the store and keep walking until you think, "geez, have i timewarped back to the 70's?" STOP, your there.
http://www.spencersonline.com/good luck i your hunt!