Sketch comedy comprises a series of short comedy scenes or vignettes, called "sketches", commonly between one and ten minutes long. Such sketches are performed by a group of comic actors or comedians, either on stage or through an audio or visual medium such as radio and television. Often sketches are first improvised by the actors and written down based on the outcome of these improv sessions; however, such improvisation is not necessarily involved in sketch comedy. An individual comedy sketch is a brief scene or vignette of the type formerly used in vaudeville, and now used widely in comedy and variety shows, talk shows and some children's television series (such as Sesame Street). Warner Bros. Animation made two sketch comedy shows, including Mad and Right Now Kapow.