This paper presents the concept of a “black box” as a tool for analyzing virtual worlds. The concept comes from the field of Science & Technology Studies (STS) and we employ it here more specifically to study one such virtual world in particular, Project Entropia. The concept of a “black box” is used to describe the developers’ efforts to hide or to build certain assumptions into the very fabric of the virtual world in order to get the players to perform certain prescribed roles. The concept is also used to describe players’ efforts to open up this black box in order to get access to and play other roles – roles not prescribed by the game publisher and that in some cases function as a threat to the publisher’s business model. The focus of the analysis is on the imperative to “pay to play”. This imperative is essential to the developers of the game since Project Entropia does not employ the usual subscription-based revenue model that most other Massively Multiplayer Online Games (MMOGs) use.