The Exploratorium in San Francisco is developing "Geometry Playground: An Immersive Learning Laboratory," a four-year collaborative project with playground designers Landscape Architecture, Inc., the Science Museum of Minnesota, and three science and children's museums around the country (Brooklyn Children's Museum, Sciencenter - Ithaca, NY, Science Works - Ashland, OR). Project deliverables include: an indoor 4,500 square foot traveling exhibition that includes a combination of immersive, table-top hands-on and electronic game elements on spatial and mathematical learning (Shape Garden, Surface City and Pattern Jungle); outdoor versions of selected exhibits from the full exhibition for public and school playgrounds and museums; a Web site that is optimized for Web-enabled mobile phones; three artist residencies related to exhibit design; and Exploratorium-staff conducted research studying variables that affect learning geometry in immersive environments. The project aims to engage public audiences with geometry in new ways both in museums and throughout communities and to improve the profession's knowledge base on learning in physically immersive environments.