Know about QR codes? If you’ve spent any time around Android apps on the web you may have seen them.
They look like this
Wikipedia has a pretty good write up: http://en.wikipedia.org/wiki/QR_Code
According to the page these codes can store up to 4,296 characters and even have the capacity for error correction
I found a great site for generating FREE QR codes. I used it to generate the one above. http://qrcode.kaywa.com/
Google used a few of these during its recent i/0 conference: http://googleio.appspot.com/qr
Wonder if kids are passing notes with these in school yet???