A couple of people mentioned that there were 2 rehearsals and that perhaps I shouldn't have used the word spontaneous.  I was actually referring to the spontaneous  impact on the crowd and how they so joined the spirit of the event. When spirit is present even rehearsed events become spontaneous. As a singer songwriter, i remember playing the same song many times, but each time was like the first time when I was sharing the lyrics anew... But this only worked with a good audience...............................................