The potential of digital game-based learning remains largely unrealized, in part because designers of "edutainment" games have never understood how and why games are effective and how to align curriculum with the game world without "sucking the fun out" of the games (according to Marc Prensky). This has led some to believe that educators and instructional designers should never be allowed near a game. The failures of the edutainment industry largely result from poorly understood theory and a lack of alignment between the worlds of education and games. Games succeed precisely because they employ sound pedagogical approaches such as situated cognition, cognitive disequilibrium, and scaffolding to teach what is needed to succeed in the game. By examining the underlying principles of games and aligning them with educational theory and learning outcomes, it IS possible to create effective blended game-based learning. Instructional design is ideally positioned to guide this process. This presentation provides an overview of some of the theories that underlie games AND effective learning and explains how to align these two worlds.