BoingBoing has an entry about a capsule vending machine at Foo Camp which sold little gears, motors, switches, and other spare parts.

Hmm, what might Penguicon do if we had one of those vending machines? It would be neat to fill the capsules with iButtons. That's a cheap uniquely identified computer chip, which can hold a smidgen of data, enclosed in a tiny stainless steel can. You touch it to a contact to transfer the data.

But what to do with it? Would purchasing an iButton for $.50 at Penguicon...
Grant entry into some kind of alternate reality game or scavenger hunt, which requires you to find the contact points around the convention, and touch the chip to them?
Operate a beer-dispensing Keg Bot like they did at DefCon?
Let you register your head-count presence at a panel or other event?
What do you think?