Advances in gaming and other entertainment technologies are evolving rapidly and create new conceptual challenges for understanding and explaining the user experiences they can facilitate. The present article reports a prospective study on a particularly promising entertainment technology of the future: Interactive storytelling (IS). Integrating various streams of computing technology, such as advanced visualization, natural speech processing, and autonomous agents, IS systems are envisioned to offer new, personalized and thus unique kinds of entertainment to mass audiences of the future. The authors refer to existing models of media entertainment for a theoretical analysis and analyze expert interviews with members of the international IS development community to lay out the foundations for a forecast model of the entertainment experience of future IS systems. The resulting model organizes fundamental requirements, modes of users' information processing, and specific types of (pleasant) experiences, which holds implications for (future) entertainment theory and research that accompanies further development of IS media. © 2012 The Author(s).