Gordon Pask's conversation theory was created in the 1970s. The theory encompasses a high-level framework for studying interactions between actors in artificial situations where people co-operate, have conflicts, follow rules, negotiate outcomes, invent new rules together, etc. Sadly, the theory is not well known. The authors claim that this is due to idiosyncratic use of terminology and radical departure from widespread research practices and accepted experimental procedures. It is argued that conversation theory furnishes a methodology for the creation and maintenance of social rule-systems. The argument is illustrated with examples from the public (car) traffic system in The Netherlands.