Multi-User Virtual Environments (MUVEs) have generated a huge wave of engaging games, yet this type of immersive online experience is rarely utilized in K-12 education to motivate students and build on the strengths and preferences they have from technology use outside of school.  In this presentation, we will discuss how immersive collaborative simulations offer new kinds of teaching strategies to help students in classroom settings master sophisticated skills they will need when they leave school, such as collaborative inquiry and complex problem solving. As an example, we will describe River City, a middle school science curriculum that has the look and feel of a videogame, but is a rich and complex learning Standards and assessments. experience based on National Science