I first heard about it through Stephanie Serrano's blog Venus De Hilo. I came across it quite by accident as I was surfing the net.
The way it works is that each member of the group makes a starter block for the round robin. The blocks are then sent to an assigned person in the group who then adds to the block. Since this is an improv group, just about anything can be added to the block. The emphasis is on improvisational and liberated piecing.(if you are curious you can read the complete rules here, or see examples from past round robins here).
This is the starter block I made for the round robin. It has been sent to the next person in line. I am looking forward to seeing what will become of it after it has traveled to all 5 members!
Each member was also asked to make a label for the quilt which every member of the group can sign and date.