Croquet-based learning environments should combine a rich media vocabulary with a distributed multi-user social experience. Such environments can provide unique opportunities for creating and delivering experiences that enhance online teaching and learning. Designing a user interface for such collaborative spaces presents several unique challenges. To enable productive interactions between users of such spaces requires that software designers choose what sorts of social interactions and cues to support such interactions within the collaborative space, and which to avoid. Design considerations are further complicated by the need to accommodate usability expectations created by users who are familiar with modern video game conventions while at the same time creating a user interface that provides an accessible path to the novice user of three-dimensional collaborative virtual environments. In this paper we examine how the user interface must explicitly address the boundary between private and public in a virtual collaborative social space, and propose a set of initial user interface conventions so that we can start the trial and error process of developing the optimal user interface for Croquet-based collaborative spaces to support learning and instruction.