Hmm; they appear to be a bit sparse on detail if you have images turned off. iCandy is a website that lets people associate QR codes (2-d barcodes) with music, video, or websites. Print out a card with the QR code, hand it to someone else, and they can hold it up to a webcam (with the application running, of course) and it plays or browses to whatever the code is linked to.

It's mostly for music, linked to iTunes (hence the name) and last.fm. It's a research project that several people at my lab have been working on for the last couple of years.