Constitution and Citizenship Day, United States September 17

Recognizing the signing of the United States Constitution on Sept 17, 1787 by Constitutional Convention this day is held as a federally recognized holiday. Educational institutions that receive federal funds are required to have instructions on the topic today. 

In addition to this day being Constitution Day it is also celebrate as Von Steuben Day. Baron Friedrich Von Steuben was a German general who offered his service to General George Washington during the American Revolutionary War. It is was mostly through his efforts that the Continental Army was able to go from a ragtag force of undisciplined man with guns to a coherent fighting force that would come to defeat the British. Von Steuben created the first manual of military drill. This day is seen as a celebration of German-Americans and there are festivals recognizing this. Normally on the third Saturday of the month. While I can not be sure this is accurate, I did read where the scene in the movie Farris Bueller's Day Off with the parade was a Steuben Day parade.