Share 'MLK day'

My bud told me that Az is the only state that doesn't celebrate Martin Luther King Day, I wonder is that true?? I've never really understood why we celebrate some stuff, why don't we have a Pocohontas Day, or John Lennon Day??!! Anywayz...I have to work this day, and all the Administration crew don't, and I don't even get paid extra for it! Not Fair!