This document discusses the development of a sustainable online game to motivate pro-environmental behavior. It notes that developed countries are responsible for most environmental impacts despite a small population. The game aims to get people to take communal sustainable actions in the real world by setting challenges and rewards. Focus groups, workshops, surveys and trials will be used to engage with the public and iteratively design the game. The goal is to understand what motivates people to act sustainably and to test using a game to promote positive environmental behavior change.