It's National Donut Day, and a new survey found 90% of us don't know there's some real history behind it.  The Salvation Army started it in 1938 to honor the "Donut Lassies," a group of women who served donuts to soldiers in World War One.

So it's not just a marketing gimmick.  But yeah, it is sorta kinda that too...Here are a few donut deals you can take advantage of today..

If you buy any drink at Dunkin' Donuts, you get one donut for free.

You can get a free donut at Krispy Kreme just by walking in the door.  No purchase necessary.

Walmart is giving away over a million free glazed donuts today.  Just head to the bakery section at any Walmart Supercenter, or participating Neighborhood Markets.

Entenmann's is running a contest through their website where you can suggest a new donut flavor.  And if they pick yours, you win $5,000, plus free donuts for a year.

Cumberland Farms is giving out free donuts if you buy coffee or any fountain drink.  But only until 10:00 AM.

And the Salvation Army is holding free donut events all over the country.  Just contact your nearest location for more details.