The U.S. Environmental Protection Agency (EPA) developed this guide to provide advice, ideas, and inspiration to teachers, school administrators, and others for planning a hands-on environmental day at school. Many of the tips and ideas in this guide come from "Make a Difference Day" events supported by EPA. EPA launched its "Make a Difference" campaign in October 2003 at an Environmental Symposium for middle and high school students held by the City of San Diego Environmental Services Department and the San Diego County Office of Education. EPA also supported Environmental Challenge days in May 2004 and May 2005 at Mechanicsburg Middle School in Mechanicsburg, Pennsylvania. EPA also assisted Kingsview Middle School in Germantown, Maryland, with the school's "It's a Green Day at Kingsview" event, held in April 2005. EPA hopes that schools across the country will embrace the ideas presented here and involve their students in environmental studies and activities. A list of related resources and a sample schedule are included.