"simSchool" is a classroom simulation program funded by the Preparing Tomorrow's Teachers to Teach with Technology (PT3) program of the U.S. Department of Education. Just as a flight-simulator immerses a player in the complexities of flying a plane, "simSchool" immerses novice teachers in some of the complexities of teaching 7th-12th grade students who possess a variety of different learning characteristics and personalities. The simulation is designed to serve as a "virtual practicum" that augments teacher preparation programs by supporting the development of teaching skills prior to field experience in real classrooms. This article outlines why simulations are needed in teacher preparation. Then, it gives a brief tour of "simSchool"--what one would see in the virtual classroom, the outlines of the artificial intelligence engine that underlies the interactions between the teacher and the students, and the psychological and learning theories behind the student personalities and teacher actions. The authors invite critical review of their basic assumptions and the components and connections they have designed to create an educational, epistemic game of teaching. (Contains 8 figures.)