We present a system for public interaction during presentations of non-interactive readymade (canned) materials such as films or pre-composed performances. Using concepts of user back-channeling, moderator and shared canvas, the system allows a significant part of an art piece that is actually happing "in the heads" of the audience to be shared in parallel or in sequential manner with the main show. We also briefly present the historical background of the blind manipulation of symbols (canned contents) and argue that a new cognitive paradigm is at work with user interaction in computer-based entertainment and digital art.