CitiTag is a wireless location-based multiplayer game, designed to enhance spontaneous social interaction and novel experiences in city environments by integrating virtual presence with physical. In the first version of CitiTag you roam the city with a GPS- and WiFi-enabled iPaq PocketPC in search for players of the opposite team that you can ‘tag’. You can also get tagged yourself if one of them gets close to you. Then you need to find a friend to free you. Urban space becomes a playground and everyone is a suspect.

(via we-make-money-not-art)