In this article, I investigate the ways in which improvisation occurs and works in stand-up comedy. I introduce a continuum model of composing and improvising and for understanding and classifying generative and nongenerative performances. The model reflects the fact that cognitive neuroscience research on creativity and improvisation provides evidence for the claim that composing and improvising are two species of the same genus (selective creation), and the differences between generative and nongenerative performance are not categorical but vague, admitting of a (...) continuum model. The model is applied to standard cases of stand-up comedy to illuminate the specific ways in which improvisation and composition are present in stand-up comedy, and the ways in which stand-up comedy performances are mixtures of generative and nongenerative elements. In addition, I address some of the reasons why such understanding is important and useful. (shrink)