How Many Advents?

How many Advents are there? Pastor Chris spoke on this second Sunday of Advent about the case you can make for there being several of them. But that's nothing new: Bernard of Clairvaux said the same thing in the 11th Century. Maybe one way we can prepare for the Advents of Christ is to take a cue from John the Baptist. What did he do and say to get people ready for Jesus?