Congress requires schools to celebrate the Constitution by holding an educational program on September 17 each year. Here are a few good places to locate material your district or school needs for Constitution Day:
Visit the American Bar Association for lesson plans, interactive features and games, conversation starters and information on landmark Supreme Court cases.
Drawing to win a classroom set of the Pocket U.S. Constitution
Download 2010 Constitution Day artwork
Step back in time and sign the U.S. Constitution online
Test your knowledge of the Constitution
Access K-12 lesson plans on Constitutional topics
Purchase a set of the Bill of Rights Poster Series
The Library of Congress website includes primary sources (the Constitution, Bill of Rights, etc) as well as links to American Memory and lesson plans. A good source for other sources is the Gwynedd-Mercy College library website. This page has links to many other sites including the National Archives, and Our Documents. Additionally, check out Congressional Quarterly's resources.
Lastly, three of my favorite places to find information about the constitution is the Center for Civic Education (author and distributor of We the People: The Citizen and the Constitution material and We the People: Project Citizen), the Constitutional Right Foundation (author of the annual Mock Trial competition), and the Campaign for the Civic Mission of Schools.
As you can see there are multiple opportunities to do something educational for Constitution Day this year.
According to the Federal Register: May 24, 2005 (Volume 70, Number 99): The Assistant Deputy Secretary for Innovation and Improvement announces that, pursuant to legislation passed by Congress, educational institutions receiving Federal funding are required to hold an educational program pertaining to the United States Constitution on September 17 of each year. This notice implements this provision as it applies to educational institutions receiving Federal funding from the Department.
NARA - Observing Constitution Day