Complex urban development projects require the involvement of multiple stakeholders who can all significantly affect their budgets, acceptance and overall success. Although a number of participatory processes have been developed for such scenarios, challenges such as maintaining long-term participant motivation and reaching traditionally underrepresented members of the population remain. Serious games have been used in various other contexts to motivate participation and promote the understanding of complex issues, but not in a co-located participatory setting. Play!UC seeks to investigate to what extent computer games can be used to support participatory processes in urban development projects. By examining game mechanics from existing and novel game approaches and their potential for use in participatory processes, Play!UC aims to create a toolbox of relevant mechanics for urban development scenarios. These mechanics will be tested in a total of three Living Lab environments in Holland, Belgium and Austria, resulting in a tested suite of applicable game-based methods that can be used in urban development and other participatory contexts