I remember as a tot in elementary school there was an assembly on May Day. There would be a May pole on the stage and a few lucky students would walk around the May pole wrapping ribbons around the thing. Later I found that the holiday was associated with Communism.
I also remember when I worked in Denver the staff would be dragged to a local park for a May Day celebration, and someone remarked "Where are the Communist flags?" We ate cold chicken then went back to work. We didn't have a may pole.
May Day has a double meaning in the United States. It is a minor spring celebration and is also tied in with left of center politics. The Occupy Wall Street people want to make a big to do for today. I wonder if children are still forced to dance around May poles? Apparently so, at least in Portland Oregon.