In this paper, we propose an environment to support collaborative modding, as a new way to learn a subject. Modding can be defined as the activity to modify an existing game with dedicated tools. In a constructivist approach, we base our work on the assumption that modding a learning game can help learners to acquire the concepts of the subject concerned. We also think that modding in collaborative settings can help learners both to learn the subject and to learn to collaborate. We first propose a framework to support collaborative modding activities based on four components: the game, the Game Development Kit (GDK), contextual discussions and a knowledge map. We then propose an architecture that integrates these components on a unique platform. We finally present the results of a first exploratory study that demonstrates the feasibility and the interest of this approach for learning and the need for integrating collaborative tools in a unique environment.