When I was at a recent Social Media Club meetup, I met Sarah Evans, and was greatly impressed with her custom nametag. She had generated a QR code with her contact information, and added it to her nametag. Very clever idea, I thought.
For the uninitiated, per Wikipedia:
A QR Code is a matrix code (or two-dimensional bar code) created by Japanese corporation Denso-Wave in 1994. The "QR" is derived from "Quick Response", as the creator intended the code to allow its contents to be decoded at high speed.
QR Codes storing addresses and URLs may appear in magazines, on signs, buses, business cards, or just about any object that users might need information about. Users with a camera phone equipped with the correct reader application can scan the image of the QR Code to display text, contact information, connect to a wireless network, or open webpage in the phone's browser.
So I could be cool, too, I created my own QR code at Kaywa, using my LinkedIn profile URL as the 'base'. I plan to use it to make my own nametag for group social events.

And here's one that redirects to my Card.ly page:

Feedback welcome - I'm curious if someone could "shoot" their smartphone at a computer monitor and still be able to decode the image. Also, have you experimented with QR codes at all?