Improvisational comedy

Improvisational comedy is comedy that is performed with a minimum of preparation concerning subject matter and structure. The performers make up their material spontaneously in their performances, typically following a general theme and format.

Many silent filmmakers like Charles Chaplin and Buster Keaton used this approach in the making of their films in which they worked up their gags as their films were produced and changed the film plot accordngly to fit.

In modern times, stand-up comedians like Robin Williams and troupes like Second City[?] used improvisation in their performances.