This research investigates the potential of Augmented Reality (AR) technologies, specifically handheld computers, to create an emotionally compelling, rich context for collaborative learning. Building on work in collaborative learning, we sought to design games requiring positive interdependence, promotive interaction, individual accountability, interpersonal and small group skills, and group processing. While the collaboration within groups was strong and successful in the first generation AR games, the collaboration between groups was limited or non-existent. Several new game play elements added to a new engine created a more dynamic game play experience. These features included time dependence, cascading events and distinct player roles. In subsequent iterations of AR games, we have found these new features to be effective at fostering collaboration, which in turn scaffolds a more authentic investigation process