Plickers is a powerfully simple tool that lets teachers collect real-time formative assessment data without the need for student devices
May 4, 2015 at 13:36:19 GMT+2 - permalink -

- https://www.plickers.com/

QRhacker.com - Pimp your code!
January 25, 2012 at 13:11:11 GMT+1 - permalink -

- http://www.qrhacker.com/

How to put your logo in a QR code - Hack a Day
September 18, 2011 at 16:09:13 GMT+2 - permalink -

- http://hackaday.com/2011/08/11/how-to-put-your-logo-in-a-qr-code/