Oh, and see, this is where political incorrectness comes into things at our house.
We took it upon ourselves at such junctures to investigate the origins of the Flying Spaghetti Monster. (Kansas school board, "teaching the controversy" etc... and most critically from your perspective, the nifty sketches of the "Museum of natural Science" showing cavemen riding dinos.)
It depends on your kid; mine always goes for snark. But she's also always had the ability to rein it in when needed, too-- she understands that her friends who are Evangelical Bible literalism Creationists won't appreciate it no matter how she points it out, so she doesn't. She just grins on the inside.
