In this article we use ideas from theorists associated with the “new materialist” or “posthuman” turns in contemporary philosophy in order to challenge the conception of the musical subject posited in aesthetic contemplation advanced by what we term the “pedagogical music world,” and to pursue the possibilities afforded by an aesthetics of intra-action exemplified in practices of the musical “jam.” We return to ancient Greek conceptions of music and leisure (mousikē and scholē), mediated by posthuman theoretical concerns in an examination of the nature of musical affect to argue that an aesthetics of intra-action necessitates a distributed and immanent notion of musical agency rather than individual and transcendent one. Through this discussion, we attempt to trouble the ideas put forth by the pedagogical music world to illuminate leisure potential as imagined in the “posthuman band.”