I found out from A Thrifty Mom that National Donut Day is actually an event created by the Salvation Army in 1938 to honor the women who served donuts to soldiers during World War I. This year National Doughnut day falls on Friday June 4th.
You can get a free donut with any beverage purchase atDunkin’ Donuts
Krispy Kreme has also announced that you can get a free donut, no purchase necessary.