Here's a video of a lovely rite, via Derek. I know very little about it at the moment - and still find it extremely affecting. There is a bit of brief explanation in the first few seconds, and then the rite begins.
"Venite, venite, venite, filii; audite me : timorem Domini docebo vos." ("Come, children, hearken to me: I will teach you the fear of the Lord.") The movement and the words are beautiful, I think - as is the chant. Derek also points to a PDF about it; I'll post again as I learn more.