Instructional designers in the Learning Games Lab at New Mexico State University have developed a specific approach for the creation of educational games, one that has been used successfully in over 20 instructional design projects and is extensible to other developers. Using this approach, game developers and content experts (a) work collaboratively to ensure educational goals and outcomes are appropriate for the learner and the learning environment, (b) immerse themselves' in both content and game design, and (c) test extensively throughout development with members of the target audience. The authors describe the model, discuss the implications of this approach for the creation of effective educational games, and share case studies based on the design model in practice.