flashier flashing shoes

You've doubtless seen those cute sneakers with the flashing LEDs on the heel. Little switch in the heel triggers a simple circuit that makes these little red lights do some neato triple-flash thing. A few changes in our redesign: (1) the LEDs emit infrared, not visible; (2) there are also infrared-sensitive photodiodes behind that same window; (3) all of which, as well as the heel switch, are tied into a little PIC chip that only costs a couple of bucks. (N.B.: It's got *very* small amounts of memory for data.) OK: propose programs / uses for such a shoe.

First idea (hey, it's got some kid appeal): Sneaker graffiti. Kid plugs his shoe in each morning before school and uploads a pithy 20-character string. Every footstep broadcasts this string to nearby sneakers, which collect it. Say we splurge, buy the chip with 192 bytes of data RAM (told you they were small) -- up to eight received messages will stay on this thing. (If more than eight are received, maybe the new one randomly boots an old one, maybe it doesn't.) Kid plugs his shoe in again that evening and attempts to decipher his peers' own messages.

Maybe restrict the allowable characters (say, to the alphabet and some punctuation, 32 characters) to allow more messages in memory (5 bits per character instead of 8)?

Maybe build a portable reader with a little LCD screen for kids with even *more* disposable income?

Kick this idea around, see what you come up with.