Augmented reality (AR) enhances real-world environments by overlaying digital information and objects. The document discusses AR applications for practitioners, including educational games that use AR simulations to engage students in role-playing scenarios. Some examples provided are Alien Contact, where students work in teams to determine why aliens have landed, and Environmental Detectives, where students investigate the source of a toxin spill on a university campus. The document suggests ARIS and FreshAir as open-source platforms for creating mobile AR games and experiences that combine virtual and physical worlds.