Musical Underwear is the underwear that gets down when you get down!
(Video is NSFW if your work frowns on undergarment flashing)
Step 1: Supplies
Also you'll need a pair of underwear, i chose some awesome looking ones from American Apparel.
And lastly you'll need a phototransistor that reacts to visible light a mini audio jack with free wires (not shown) and a 3 AA battery holder
Step 2: Picture Frame Circuit
Upon opening it up i discovered the "motion activation" was just a photoresistor, but it triggered the circuit when there was NO light, and i wanted the opposite. I had lots of ideas of building complicated transistor circuits to give a resistance when a phototransistor saw light. But i decided to try just to hook up the photo transistor as a direct replacement of the photoresistor and it worked! it reacted to the presence of light!
After figuring that out I removed the circuit from the plastic casing and desoldered the microphone, speaker, and photoresistor.
See the pictures for the taking apart process.