There are so many things you can do with a QR Code Generator. At this site:
http://www.qrstuff.com/
you can create QR codes for a website, a YouTube video, Google Maps, Twitter, Facebook, LinkedIn, Dropbox, plain text, phone numbers, Skype calls, SMS messages, email addresses, email messages, contact details, and more. Imagine the possibilities of how this could be used in the classroom! Below is a QR code I created to link back to this blog: