The presentation considers artistic products and experiences: those that are primarily for users' pleasure. For these experiences, users are motivated by self-expression and playfulness rather than any usual sense of formal 'task completion'. We look at interactive experiences from arts festivals, to carnivals, to theatre, to nightclubs and raves. What can designers in this world learn from traditional UX and what can traditional UX practitioners learn from successful designs in these alternative environments? The presentation first looks at how to design walk-up-and-use products for large, flighty audiences and then moves on to the design of bespoke interactive products for single users or performers. We then finally consider one important question: How do you best design a product when its users are - quite literally - a bunch of clowns?