I really need to start using QR codes. This post has a link to a custom QR code app and many ideas of how to use them in the classroom, like having a math problem projected on the board for the kids to get.
QR Code Maker - Free QR code Generator. Use for parent night at school! Sooooo easy. Create your own QR Barcode for parents to scan with their smartphones on meet the teacher day! Include contact info, a link to a syllabus online, supply list... Everything!