This paper briefly describes two interactive multimedia research and development projects, the Palenque Project (1985-1991) at Bank Street College, and the Museum Education Consortium's Interactive Video Project (1988-1991) at the Museum of Modern Art in New York City. It is noted that the designs of both prototypes share experimentation with a pedagogical bias toward discovery-based learning, feature exploratory experiences in multidimensional environments, and contain a variety of similar user interface characteristics which promote information access and manipulation. Each of the projects is described separately. Palenque is a digital video interactive (DVI) project based on a self-directed exploration of an ancient Maya site and on the perusal of a multimedia database called the Palenque Museum, which was originally designed to provide a discovery-based experience for 8- to 14-year-old children and their families at home. The Museum Consortium's project is an interactive multimedia prototype that was developed as a discovery-based learning experience for testing with adult museum visitors who have a limited knowledge of art history or art. Design features common to the two projects are then discussed, and a brief summary of the design issues that need to be addressed in their development concludes the paper. (ALF)