National Doughnut Day started on June 7, 1938 when a young military doctor by the name of Morgan Pett was sent to a military base. On his way there he stopped at a bakery and picked up eight dozen doughnuts. When he arrived at the base he started helping many wounded soldiers, and would give them a free doughnut. One man he helped was a Lieutenant General by the name of Samuel Geary. Samuel Geary decided to make a fund raiser with Morgan Pett to give every wounded soldier, and the needy a doughnut. This fund raiser was later joined with the Salvation Army. Many donut shops still give out free donuts on this day.
In honor of the day Krispy Kreme, with no purchase necessary, will hand out a free donut of choice to each customer.
Dunkin Donuts (which began the new spelling) will give out one free donut with the purchase of any beverage.
Incidentally, International Jelly-Filled Doughnut Day is widely recognized as June 8.