Richard Seymour, writing in the Guardian, traces a brief history of May Day and its continued importance for militants and the working classes:
May Day is international workers day. As such, it is – in the words of Eric Hobsbawm – "the only unquestionable dent made by a secular movement in the Christian or any other official calendar".
And while we're celebrating May Day, by taking the day off (whether we're on the clock or not), the ruling elite in the United States seems to think they're celebrating, as John Protevi points out, "Loyalty Day" or "Law Day." As he writes in a comment to that piece:
This discrepancy is not coincidental.