This paper describes HyperMem, a system to store and replay user experiences in mixed reality worlds. The experience is stored as a set of hypermedia nodes and links, with the information that was displayed along with the video of the real world that was navigated. It uses a generic hypermedia model implemented as software components developed to handle mixed reality environments. This approach is applied to an augmented museum, that includes information and gaming activities in the physical and virtual 3D worlds. The paper presents the goals of the system, the underlying hypermedia model, the type of worlds that we are considering, and the architecture and tools for replaying and repurposing stored information.