This paper presents a methodological proposal elaborated in the framework of two European projects dealing with game-based learning, both of which have focused on "quality" aspects in order to create suitable tools that support European educators, practitioners and lifelong learners in selecting and assessing learning games for use in teaching and learning processes. Both projects Uni-Game (Game-Based Learning for Universities and Life Long Learning) and Sig-Glue (Special Interest Group for Game-Based Learning in Universities and Lifelong Learning) have been cofunded by the European Commission since 2002, and both have involved organisations from different European countries, backgrounds and expertises, and as a result of this work, a "classification of games by learning purposes" and an "evaluation framework for assessing games" have been designed and placed at the disposal of European educators, practitioners and lifelong learners.