National Doughnut Day is on the first Friday of June each year, succeeding the Donut Day event created by the Salvation Army in 1938 to honor the women who served doughnuts to soldiers during World War I. The holiday celebrates the doughnut (a.k.a "donut") — an edible, torus-shaped piece of dough which is deep-fried and sweetened. Many American doughnut stores offer free doughnuts on National Doughnut Day.
How about you take your kids and measure the circumference of the Donut? Both the inner and outer rings? Can they guess which ones weigh more? Are more dense?