The document discusses using QR codes in the classroom. It begins by explaining what QR codes are and how they were invented. It then provides examples of how QR codes can be used for scavenger hunts, review games, linking to videos and websites. Specific examples described include a periodic table of QR codes and a genetics QR code quest. The document also discusses generators for creating QR codes and apps for reading them. It encourages being creative in using QR codes without mobile devices and provides resources for finding more classroom ideas.