September 17th is National Citizenship Day. Community groups around the country usually organize events to encourage residents to become U.S. citizens and voters (see National Citizenship Day: Latino Organizations Tout Benefits, Offer Help and Celebrating Immigrants’ Contributions this Citizenship Day and Constitution Week from last year).
The Best Websites For Learning About Civic Participation & Citizenship shares a lot of resources that be helpful with this recognition of Citizenship Day.
September 17th is also U.S. Constitution Day, when federal legislation requires schools in the United States to offer lessons related to the U.S. Constitution. You might find The Best Sites For Learning About The Constitution Of The United States useful.