Do you have a smart phone? If you do, go download a barcode reader app. I have one for my Android phone, and it’s simply called Barcode Scanner. I guess if wanted to, you could also carry around an actual barcode scanner, but that’s… weird.
Bill the Web Librarian at York University Libraries, and the author of the esteemed Miskatonic University Press wrote this post, in which he offers up his great idea for a Code4Lib 2010 t-shirt design. Just hover your barcode reader over the image to see what comes up. Tons and TONS of interesting applications for this technology, and many thanks to Bill for bringing the tool to my attention.