Pervasiveness can be recognized in game playing every time the boundaries of playing expand from the virtual (or fictional) world to the real world. Sensor technologies, mobile devices, networking capabilities, and the internet make pervasive games possible. In the present work, we consider pervasive mobile games as context-aware games that necessarily use mobile devices. Also we consider that smartphones are the main driver to fulfill the promises of pervasive game playing. As far as we are aware, this is the first general work on pervasive mobile game design. This thesis proposes a methodology to support the conceptual design stage of pervasive mobile games. The main contributions of this research work are twofold: (1) A novel list of prominent features of pervasive games, identified from game projects and the literature, and checklists for each feature. This feature list (and corresponding checklists) can be used to spark novel game ideas, and to help in discovering functional and non-functional requirements for pervasive mobile games. (2) A domain specific language to help in specifying activities in pervasive mobile games that use mobile devices, sensors, and actuators as the main interface elements. With the proposed methodology, designers can discuss, identify, verify, and apply important features of pervasive mobile games. Also, due to the lightweight nature of the methodology, designers can easily catch the big picture of the games by keeping focused on the intents of the game activities, and not getting lost in the source code.