Why Celebrate Labor Day?

I know we're not going to argue, but why do we always have the first Monday of September off of school? We just started, do we really need a day off? (I'm fully aware that we DO need the day off, I'm just asking if anyone knows why.
If you care to take a minute and do some research, look up a brief history of Labor Day.  Email me a 3-5 sentence summary and earn five bonus points! Be sure to email a response before school starts on Tuesday. And check back for the answer.