I have an app on my Droid that reads them. It will scan any barcode. It has multiple uses, though, I could scan a barcode on a product in a store, and it will give me a list of retailers that sell it, as well as their prices and potentially reviews; I could scan an ISBN off a book and it will give me information on the book, etc.
They have barcodes on the pinball machines in the Pinball Hall Of Fame And Museum in Vegas, scan the barcode, it takes you to a webpage with a bit of information on that particular game, and a local realtor I know puts barcodes on his flyers for various properties that you can go to for more information, etc.