No, it's not your crazy Uncle with the glass eye ... Harold is a structure used in longform improvisational theatre that is performed by improv troupes and teams across the world. In the Harold structure, characters and themes are introduced and then recur in a series of connected scenes. Harold was first performed in California by The Committee in 1967 and further evolved by Del Close in Chicago in the 70's and 80's.  Amy Pohler, Mike Myers, Zack Woods, and pretty much every comedic actor you can think of has performed in or is performing Harold.