here's my latest bajillion dollar idea, inspired by having just received my very first manicure last weekend. (this is the sort of thing that happens when dear friends get married.)
what if you could choose a nail polish that omitted music, very softly, the entire time it coated your nails? this way you could sit at work or ride the train with your hand casually resting on the side of your head near your ear and be listening to beautiful music (or death metal) at the same time. as your nails started to chip you might hear noises like cd glitches or record skips. and it'd be a great pickup line, "hey, is that erik satie coming from your fingernails??" or you could write your OWN music and then wear it around on your hands. and holding hands could bring forth the purest harmonies, or even lovely dissonance. (if your partner wasn't into wearing a color on her/his nails, there's always the option for clear polish.)
i really think i'm on to something here. any backers out there?