In particular, the middle act is about a group called Improv Everywhere that takes the flash mob [Ed: do you think anyone remembers those?] concept to a whole new level. The show profiles a few of their missions to "[cause] scenes of chaos and joy in public places" and follows up with commentary from the people whose lives were unknowingly the focus of the group's performances. Listening to it last night, I couldn't decide whether I thought that the Improv Everywhere was creating some kind of beautiful magic in a mundane world or just being egotistical and creepily intrusive. Maybe it's both, or something in the middle.
It's likely my general reservations about improv comedy are a factor in my reception of the story.