For the last few game nights with the kids, we've been playing a role playing game I developed--basically a very streamlined version of GURPS set in the Olympics. They are all loving it, and the twins have finally overcome their fear of combat and were enthusiastically taking actions to take down a hungry cougar. Dot (a lizard) decided to jump on his tail to distract him, while Dash (a child) started digging frantically (he has been very fond of his shovel) and found several pails of water (why not? it was a beach and we are always losing pails there), which he then used to hit the cougar on the nose. This involves a lot of rolling and counting up dice, and taking away hit points when they are injured, and adding them on when they find healing herbs, so besides being a lesson in natural history and divergent thinking, it's a great math activity.
The next day, Dash was sitting more-or-less quietly while I read out loud to the older kids, until I noticed what he had drawing. On both sides of two sheets of paper, he had drawn recognizable scenes of his four favorite Magic: The Gathering characters and was conducting duels between them.
We may have the world's geekiest preschool curriculum.