The "Playful Invention and Exploration (PIE) Institute" is a three-year project to increase the capacity of museum educators and exhibitors to design and implement technology-integrated inquiry activities for the public. The collaborators include the Exploratorium, MIT Media Lab, Science Museum of Minnesota, Fort Worth Museum of Science and History, Explora Science Center and the Children's Museum of Albuquerque. The deliverables include a portfolio of technology-rich activities, professional development institutes, online educator resources and a handbook of pedagogical design principles for museum educators. This project builds upon prior NSF supported work that developed the PIE Network, which among other things developed the "cricket," an inexpensive computer that makes informal learning inquiry activities more compelling. This project has the potential to impact both the theory and practice of informal science education in museums. It will implement new theories and tools that represent a new approach to engaging and supporting visitors' learning experiences using play and experimentation that mirrors the processes of laboratory investigation. It also provides an innovative model of collaboration that develops and implements a major complex project by bringing together science centers with unique and complementary expertise.