Ye Olde Badde Apple will be closed on Labor Day Sept. 7 in honor of the holiday.

"The first Labor Day in the United States was celebrated on September 5, 1882 in New York City. In the aftermath of the deaths of a number of workers at the hands of the US military and US Marshals during the 1894 Pullman Strike, President Grover Cleveland put reconciliation with Labor as a top political priority. Fearing further conflict, legislation making Labor Day a national holiday was rushed through Congress unanimously and signed into law a mere six days after the end of the strike. Cleveland was also concerned that aligning a US labor holiday with existing international May Day celebrations would stir up negative emotions linked to the Haymarket Affair."

from Wikipedia
more info here about how Labor Day should have been May 1st.