http://www.kids.gov/

Kids.gov - The Official Kids Portal of the U.S. Government

Kids.gov is the official kids’ portal to the U.S. government. With links to over 1,200 web pages from educational organizations, schools, and government agencies, it’s geared to the learning levels and interests of girls and boys in grades K-5 and 6-8.

All major curricular areas as well as "arts", "careers", "fun stuff", "money" "health/fitness" and "government" resource categories are featured.

While it is their mission to link primarily to government sites written for kids, many of the sites we’ve selected also provide lesson plans and classroom activities for teachers. The Kidsgov Free for Teachers page also has free publications, colorful posters, and practical lesson plans,