Not all aspects of urban social life are predictable and rational. Urban public space is characterised by tensions between efforts to regulate behavior and stabilise meanings, and the diversity of everyday social practices. This paper examines such tensions, by focussing on how public spaces in Melbourne, Australia frame possibilities for play. Play includes unplanned, non-instrumental interactions between strangers, and explorations of the physical and symbolic texture of the urban landscape. The paper focuses on three dimensions of urban social life where spatial design has a critical influence: performance, representation and control. These dimensions highlight how the meanings, desires, behaviors, and even the built forms of urban public spaces are shaped by a constant dialectical interplay between instrumentality, normativity and play.