Sketching leverages human skills for various purposes, such as content authoring. This paper explores the different aspects of sketch-based interaction in augmented reality. We explore the design space of sketching in in-place augmented reality with particular attention to AR games. We propose a contextual model that offers a framework for the exploration of the design space by the research community. We describe different case studies of sketch-based AR games we developed based on our shape-based tracking library and our sketch-based 3-D game engine. We finally present user feedback from our games and introduce guidelines for AR game designers focusing on sketch-based interaction.