Sibling Cooperation

Three or four years ago we met a family with 10 kids who spend about half the year touring the country singing and playing.  Our kids have learned several neat songs over the years from their CDs and website.  Some of the children noticed that they would be performing in Oblong last Monday evening on their way home to Iowa from one of their tours.  So we went to see them.  They had several new songs but one of the most impressive is an instrumental they call Sibling Cooperation.  I took the video with my phone with everyone tapping their feet and the pew shaking so it is a little shaky in places.
Something amazing happens about 1 minute into the video and then it gets doubly amazing at about 2 minutes into the video.