Effective classroom discussion is improvisational, because its effectiveness derives from the fact that it is not scripted. Instead, the flow of the class is unpredictable, and emerges from the actions of both teachers and students. In this article, I apply principles from training classes for improvisational actors to provide practical suggestions for teachers. To identify the improvisation community's own views on creative collaboration, I draw on recent observations of rehearsals, performances, and improvisation training classes, and interviews with actors and directors. I conclude that teachers could become more effective discussion leaders by becoming aware of improvisational acting techniques, and I make a case for instructing teachers in improvisational exercises.