In this paper we present our approach of using gamelike techniques for designing wearable computing solutions for the Paris Fire Brigade, consisting of namely a board game and a virtual environment for collaborative prototyping during simulated interventions. We provide first results on the approach's benefits and difficulties. Keywords User-centered design, participatory design, prototyping, wearable computing, serious games, fire fighting ACM Classification Keywords D.2.2 [Software Engineering]: Design Tools and Techniques, Evolutionary prototyping; H.5.2 [Information Interfaces and Presentation]: User Interfaces--Prototyping, User-centered design