I was in a discussion about QR (Quick Response – which are two dimensional barcodes), and was told about baseball cards using this data to generate 3D images. You hold the card up to your webcam, and on the screen you get an image.
Some stats here, and links to campaigns by Ford and Pepsi and more info, as usual, at wikipedia
[youtube]http://www.youtube.com/watch?v=QAjEGqGnpFI#t=00m30s[/youtube]
I had seen the same thing with Mini Cooper a few months back, I think there will be a lot of interesting stuff on this front:
[youtube]http://www.youtube.com/watch?v=HTYeuo6pIjY[/youtube]