I feel like at some point on the bgdf people were discussing barcodes in games, where cards would have barcodes on them and you'd scan the card to get information that you couldn't fit on a card.
I guess now there are iphone apps that can scan barcodes, like this one:
http://www.ismashphone.com/2009/05/red-laser-the-first-accurate-iphone-b...
This seems like a great resource for game design. Have people done this yet? Does enough of the population have iphones to make this possible?