Cost-effective, easily replicated program is a win-win situation for high schoolers who teach science and for their elementary students. The thank-you letter from Leslie, a grade-schooler in San Diego County's Ramona Unified School District, speaks volumes about the excitement generated by "Celebrate Science"--an innovative, standards-based program that gives high school science students the opportunity to present hands-on science experiments to elementary children. This program was established with support from then-school board member Christopher Smith, a physicist at UC San Diego's Center for Theoretical Biological Physics. It's a learning experience both for elementary school students who participate in its interactive biology and chemistry demonstrations and for upper-division students who plan and present living learning opportunities--designed by the students who present them to align with appropriate grade-level science standards.