Well it apparently was spontaneous, according to Bob Burger the musician whose band was playing the party. The only part that he knew about was that Jon was going to come up and sing a few with them, which Jon did to move the party from the dining area down to the dance/party area of the party. The Govenor of NJ is the one that set things off when he led the dancing with the Lindy during WSYCGO.After that according to Burger, it just took off. He said it was surreal to have them all up there. Some of the songs they did were: Long Tall Sally: McCartney did this unwarmed up in the original key spot on according to Burger. Midnight Hour, Honkey Tonk Women, and Roger Waters sang Wish You Were Here.
I would have paid big bucks to see this bunch play together.