Google set up a booth on the streets of Austin where passerbys could "pay" for a cupcake by sharing a branded pic with their social network. To one-up them (and brilliantly point out how people were just made pawns in giving Google free advertising on their social network) Zappos set up a booth right next to Google's asking people to pay for a happy surprise with the cupcake they just got from Google. No free advertising, just the cupcake, and out came an item from Zappos.com. Ballsy. We like that.