Rules are used by Computer Games to evaluate losses, gains, changing items and actions of the players. In addition, they reinforce realism and playability, especially in training situations where Knowledge is complex and expert (e.g. best practices acquisition in crisis management, decision making in complex socio-technical systems…). To evaluate items and actions, we propose a dynamic solution using “participative rules”. In this approach, based on Computer Supported Cooperative Work and Knowledge Engineering, the rules base is directly generated from a special discussion forum which contains successive versions of the textual rules continuously discussed and co-built by the designers’ community, in strong relation with the players’ community. This paper resumes a “Work in progress” recently presented with more details to the Game Community, but it extends it by adding the point that, beyond the ”Serious Games” field, the notion of “participative rule” that we are exploring, could interest more broadly Human and Social Scientists who seek new ways towards effective evaluation methods.