Spontaneous, creative activity applying the elements of an art form:
In Dance, movement that is created spontaneously, either free-form or highly structured.
In Drama, a spontaneous enactment taking on roles and situations to create dramatic action and extend an idea; usually short and are structured into a complete little play.
In Music, spontaneously extending and varying music ideas in response to initial material or responses invented by other performers in an ensemble.
In Media Arts, organisations that enable and constrain media production and use.