People spend hours waiting in line each year, yet this waiting is often spent in inactive, unhappy, or isolated ways. In this paper, we explore the use of exergames to improve waiting experiences and increase physical activity by providing opportunities for exercise and social interaction. To do so, we present the design and study of JumpGym, a multi-player exergame that receives input through physical jumps from players for use in public spaces where people have to wait. We share findings from a lab study and a field deployment conducted at a bus stop. Our findings indicate that playing JumpGym influenced perceived waiting time, physical activity, and social interaction of participants. We share design strategies that were identified as key to obtaining these results.