On a completely different note... parents have some good reasons to NOT let their children play Grand Theft Auto, but there's an old Simpsons-themed equivalent that I've shown to a lot of kids, and they've all LOVED it: The Simpsons Hit and Run.

It's an older game and I've found it performs badly on multi-core machines unless you set processor affinity for it to a single processor, which can be a pain, but otherwise it works great. It's infused with Simpsons-style humor, so if that fits your family values, it's a lot of fun.