It always amazes me how much cool stuff has come from Xerox's PARC (Palo Alto Research Center) branch. Graphical user interfaces (i.e. Windows and the Mac both use GUIs), the mouse, Ethernet, e-mail, WYSIWYG editors—all of these and more came from the minds of employees at PARC. Xerox really failed in the early 70s by not jumping on these experiments. However, that didn't stop people like Steve Jobs—who based many of the Apple features on things he saw during a trip to PARC—from capitalizing on the things the creative minds at PARC were creating.
Something the guys at PARC have been working on for a while now is DataGlyphs(r). I first remember reading about this probably a few years ago and at the time I didn't really give it much thought (other than to say: "Hey, that's cool.") I was watching TechTV last night and they brought on a researcher from PARC. He gave a demo on using a normal scanner with some custom built software that relied on DataGlyphs to read in the positions of chess pieces on the board. While this in itself wasn't all that practical of a use, DataGlyphs themselves are.
Essentially DataGlyphs give you the ability to embed binary data into a print-ready material that in unobtrusive to the human eye. It essentially is a replacement for the barcode system we currently use. To represent data, it uses a series of backward and forward slashes that represent ones and zeros.
Because the human eye doesn't easy recognize these patterns, you can begin to encode them into pictures and even text-based characters—and they become undistinguishable to the human eye. All we see is the original image or text. There's actual tons of useful applications for this technology. For example, imagine all your documents where printed to paper each character was actually DataGlyph. While this text would be completely readable by a human, you can now scan that document into a computer and have it understand exactly what the document says—no OCR process needed, which means you eliminated the errors that normally occur with OCR process.
There are tons of really cool uses for this. Imagine a drivers' license with nothing but your picture on it. All of your sensitive data could be hidden using DataGlyphs within your actual picture. You could even use it as a form of encryption. I could hand you a document that talks about how my weeks been, but contained within the document are machine readable DataGlyphs that actually give details on the top secret project we're working on.
I recommend spending some time someday just browsing through the PARC web site—they've always got interesting stuff going on.