Of course we all know about the Declaration of Independence and we all talk about the Constitution we kind of mush the two things together. They are not the same documents. Constitutional Congress last met on September 17th, 1787 to sign the Constitution, a work long labored over that guides and protects citizens of the United States. It is not perfect, but strives to be as comprehensive as possible, including all as best as the forefathers could imagine at the time. The document went into effect on March 4th, 1789.
How to celebrate – Read the Constitution. Appreciate the efforts of those men far beyond their time. Try to come up with a better Constitution yourself.