Atheists & Agnostics

Kids can certainly relate to that one. Whether or not the kids end up believing religious rubbish later on, they'll retain the notion that people who damn their neighbors are just mean people who should be avoided.

I have absolutely no hesitation telling a child that some person who thinks s/he has the right or the wisdom to determine who will be tortured for eternity is just plain mean because that's what those people are. I can prove it with their own book, too.