G-rated Simulation Games?

jhl at school asks: "I am a Math and Technology teacher at a middle school, in rural Maine, where all of our 7th and 8th graders are given iBooks that they can use. What they are allowed to do with them is kept within strict limits, and it must be educational. I stay with then after school, and during this time they are allowed to use them for fun -- within limits (no violence, and nothing sexually explicit). I bought a copy of 'The Sims', at the kids' request, but the principal says it's too racy (polygamy is allowed, characters can climb into bed together, and so forth). What simulations our out there, where these kids can play in virtual environment, but keep it G-rated as my principal would like. Alternately, might there be some information to help the argument that 'The Sims' has educational value? I've found nothing I thought was objectionable - but this is a very conservative community. Thanks on behalf of my kids, who could use a little fun."