In this design case, we describe The Handwavey Game (Handwavey)--a tabletop, cooperative role-playing game created to study how people can come to converge on novel physical gestures around meaning. In Handwavey, players are novice wizards who cast spells through signaling abstract images with hand movements: success is rewarded in-game and failure has humorous in-game consequences. This case walks through the path of exploration and development from the starting point of a research question to the development of game mechanics and concludes with a set of design recommendations for people interested in designing novel games with specific research or learning meta-goals.