When I taught Sunday school to a precocious bunch of fifth- and sixth-graders, I used to ask, "What about Christmas is not in the Bible?" They were quick to go for the obvious: Santa, the reindeer, stockings, the sleigh.

"OK," I would say, "but what about the three kings, the innkeeper, the stable and the animals? Where do they come from? Let's look at the text."

That is not something most of my students would readily do unless there was the possibility of one-upping their parents.