Norman Day?

Ok, so I was under the impression that July 4th was Independence Day. However, when I did a google search for the Norman Independence Day celebration, this is the website I found. Something that says that the 30th annual Norman Day celebration is July 4th, 2005. Someone want to explain why the Christmas tree is now a holiday tree while you are explaining how the celebration of our nation's birthday has suddenly become a celebration of Norman? Forgive me, but I'm just a bit confused!