This article discusses our experiments to create more engaged participation and build sustainability literacy among students in a voluntary "game lab" on two different campuses of our Japanese university. Though we found the game lab to be a successful vehicle for language learning, community building, and traversing disciplinary boundaries, it was more difficult to engage students with big ideas about environmental sustainability. We reflect on what we learnt from the game lab's first 2 years at our university's main campus and how we will further our goals to use participatory game design to promote sustainability education at our new campus environment.