For many summers the Radiation Science and Engineering Center at Pennsylvania State University has been the site of a Nuclear Concepts and Technological Issues Institute for secondary school science teachers. As a culminating activity of the institute teachers develop lesson plans, laboratory experiments, demonstrations, or other activities and projects to take with them for use in their own science classrooms. This booklet contains 20 especially creative, unusual, or well designed projects selected from those devised by the teachers. The activities are designed for a wide range of grades and some involve group work, others are presented in various forms such as simulations, games, and puzzles. The booklet is divided into three sections: "Atomic Theory Made More Concrete";"Radiation: Applications and Issues"; and "Using the Chart of the Nuclides." Appendices include additional activities and sources of materials and information. (JRH)