: The emerging tensions between the mobile application logic and the unfolding dynamic context of use belong to the core challenges of ubiquitous computing today. Starting from and with reference to our experiences with mobile gaming in a game world, combining real world with virtual dimensions, we explore the mobile play activity as a source for the development of solutions. While the mobile gamer as producer of play possibilities before the game is pretty well understood, emergent game play and the mobile gamer as producer of novel play possibilities during the game rise conceptual and technological questions.