(Yeah, I know, QR Codes aren't very "sexy" to look at, but I didn't saw any other demo for it ).
You can generate a QR Code, choose its Quality Type (meaning the redondancy in the code => its robustness to noise (like bad pictures taken from smartphones), and its Level (meaning its 'size' in QRCode world).
By the way, the size of the drawn Code is decided by the size you set inside C2 IDE. That means you can generate a very "small" Code (with a Level or 2 or 3), but display it inside C2 with a size of 600x600 pixels ! It's going to look elongated.
The demo : https://dl.dropbox.com/u/1412774/QRCodeDemo2/index.html
The plugin : https://dl.dropbox.com/u/1412774/QRCodeDemo2/pode_QRCode.1.0.zip
The .capx : https://dl.dropbox.com/u/1412774/QRCodeDemo2/QRCodeDemo2.capx
Watch out for some combinations of string size and Level. If the string is too short, the lib will trigger an error because it can't be encoded at that Level.
The code is base on the JS lib from there : http://d-project.googlecode.com/svn/trunk/misc/qrcode/js/qrcode.js
With that plugin, you can generate some quick Code to send users directly to your game when snapping the code with their smartphone.
Exemple : code for this page =