The authors use the location-based, augmented-reality game "Wayfinder Live," which one of them designed, as a case study to analyze urban play. Acknowledging the difficulty of defining urban play, they expand existing approaches to the topic by drawing on current theories about interfaces, assemblages, and coding in such fields as media and cultural studies, game and play studies, and urban studies. They consider "Wayfinder Live" as an interface--a site of both connection and translation--for urban play, one that encourages its players to test a given city's physical and social boundaries. They argue that the game offers a fruitful, if always contingent and contextual, framework for analyzing digitally mediated urban play.