The document describes the PLACE approach for prototyping location-based, social games and apps. PLACE stands for Prototyping Location, Activities, and Collective Experience. It involves starting with low-fidelity prototypes to test activities and experiences in real-world locations in small groups before scaling up to more participants. The approach was used to prototype Floracaching, a location-based citizen science game similar to Geocaching, where participants find and scan QR codes at outdoor locations to complete activities and earn badges.