Twenty-five years ago I attended P.S. 29's whole-school production of "The Shooting of Dan McGrew," directed by Jacques D'Amboise. (And I do mean the whole school, including the janitorial and cafeteria staff.) It was a great production, but something went wrong about a third of the way through, and D'Amboise stopped the action, yelled a little, and made them start the scene over. He held everybody to professional standards -- and they rose to the challenge. So did your kids, apparently, but this is not unprecedented. It is what the theater is all about!
