The Second City is an
improvisational comedy enterprise. It's the oldest improvisational theater troupe to be continuously
based in Chicago and has become one of the most influential and prolific
comedy theatres in the English-speaking world.
Improvisation is a form of theatre, often comedy, in which most or all
of what is performed is unplanned and created spontaneously by the
performers. In its purest form, the dialogue, action, story, and
characters are created collaboratively by the players as the scene
unfolds in present time, without use of an already prepared, written
script.