This paper investigates design elements for innovation contests in order to unlock the innovation potential of temporary virtual communities. Open innovation in general and particularly innovation contests have recently received considerable attention in research. Still, there has been mostly generic theorizing on the design of innovation contests to foster innovative output. Findings from an in-depth case studies in the shoe industry reveal a design with two players, the organizer and the potential participants, a temporarily very active virtual community which we denote ‘innovation mob’. With our paper, we contribute to the fields of virtual communities and open innovation by proposing a systematic approach, structured along five stages, from preparation to follow-up.