Happy Holiday. According to the United States Department of Labor website, Labor Day is a creation of the labor movement and is dedicated to the social and economic achievements of American workers. It is a curious day when thousands celebrate "labor" by not working and other thousands work instead of getting a holiday.
I don't think there is a "Sing Day" holiday, but we will make our "Labor Day celebration" tonight a Sacred Harp singing at Smyrna Baptist Church near Mt. Enterprise, Texas. Come join us. 6:30 p.m. Directions at link above.