A new social form of play taking place in public spaces, such as city parks, squares and streets that can scale up to involve large number of participants and engage players located simultaneously in dispersed areas is discussed here. This paper presents a platform that allows for the creation of interactive installations in public spaces. The FinN platform provides functionality for detecting and localizing people, by requiring players to carry identifying devices that offer many possibilities for gesture interaction (i.e., gestures such as shaking, facilitated by the sensor-bouquet of the devices). One of the deployed example installations, where visitors can interact with words formations, is presented here as a case study.