Every December, an unusual pilgrimage takes place. Thousands of people flock to the small prairie town of Northfield, Minnesota. They're going to hear the annual St. Olaf College Christmas Festival. It's not so much a concert as it is a worship service in music. Even though the school is small, the program has a following across the country, including national broadcasts on public radio and TV. We'll hear highlights from the 2012 St. Olaf Christmas Festival, which took place just last weekend in Northfield.