Steven Hoy from Tabula Digita just told me about their new learning system called Dimension U.  Dimension U is an educational game platform where elementary and high school students “compete, collaborate, and play, all while working on core curriculum from their schools.”  Consists of 5-20 minute games in subjects like math, science, history, and literacy.  The system seems to incorporate many successful elements of popular virtual environments and social games, including avatar personalization and the ability to accumulate credits for accomplishments and compete with students all around the world to earn rankings on leaderboards as part of regional and national competitions.  Also included are dashboard metrics for teachers and administrators to track individual progress.  Dimension U is aligned to common core standards.  Click here to watch the promo video for Dimension U.