The belief motivating the 4D Experience research programme is that the experience evoked by a computer system can be (at least) as important as the ostensible functionality of the system. In this report, we describe three case studies that explore the experiential approach to system development: Zap Scan, A Walk in the Wired Woods, and the Soundscape Workshops. In each case, we adopted a form of participatory design in which potential users and/or experienced artists were recruited into the development process. We discuss how the success of the resulting experiences might be explained by an underlying theoretical model and conclude with comments on the positive value of participatory design.