Pervasive gaming is a new form of multimedia entertainment that extends the traditional computer gaming experience out into the real world. Through a combination of personal devices, positioning systems and other multimedia sensors, combined with wireless networking, a pervasive game can respond to a player’s movements and context and enable them to communicate with a game server and other players. We review recent examples of pervasive games in order to explain their distinctive characteristics as multimedia applications. We then consider the challenge of scaling pervasive games to include potentially very large numbers of players. We propose a new approach based upon a campaign model in which individuals, local groups and experts draw on a combination of pervasive games, online services and broadcasting to take part in national or even global events. We discuss the challenges that this raises for further research. Categories and Subject Descriptors