My 10 favorite things about natural history to teach to little kids in public school:1) The P-Tr boundary: "About 245 million years ago, almost everything died off. Nobody really knows for sure why. After that, the Age of the Dinosaurs began."
2) Some birds had teeth: "Some of the earliest birds had teeth. All such birds died off before the end of the Age of Dinosaurs."
3) Neanderthals were different, but still they were people: "They had a skull with bigger eyebrows, and it was flatter and not as round as our skulls are."
4) Carboniferous forests: "There were these huge forests of ferns and horsetails, which were much taller then than they are now. These forests eventually died and became what we now know as oil and coal."
5) Euoplocephalus: "Euoplocephalus was a species of dinosaur (shows picture) that had a big club growing out of its tail, that it probably swung at enemies that would try to eat it."
Any more fun suggestions?