I was actually a very small part of another of these being filmed at a series of folk festivals. This one is a little more rehearsed, since some of us neophytes had to learn the tune. There are some amazing kids doing a song before hand. The "feet" are the "click track" to keep us all in tempo throughout. Can't wait for the releast, because I've forgotton how the tune goes (there's been an amazing week of traditional Quebecois music at Camp Violontrad in between and a lot of tunes have shifted that one out of my head). The subway videos are pretty grand because of people walking off the train into the music and reacting. It's also a very fun way to remind people of the folk tradition from whence they come. And Joyous is indeed why I have become more than a little obsessed with this music.