I remember giving my grandson an Advent calendar, with its two dozen closed windows, one to be opened each day between the first Sunday of Advent and Christmas. As a child he thought that all sorts of exciting things might lie behind those windows, a dragon, perhaps, or a penguin or a dinosaur. He soon discovered the more predictable reality of stars and shepherds and donkeys, and that the final window opens on the baby lying in the manger, the one who for us became the true, authentic window into the mystery we call God.