The day commemorates the times when the Salvation Army and the "lassies" gave away free coffee and doughnuts to soldiers during World Wars I and II. Over at Blue Dot the purchase of a drink will get you a free doughnut — perhaps a red velvet or a maple-and-bacon long john? — and the bakery is donating 10 percent of the day's proceeds to the Salvation Army. There's also raffles, free samples and other deals throughout the day. Check Blue Dot's Facebook page for updates.
The national doughnut chains Krispy Kreme and Dunkin' Donuts usually have promotions on Doughnut Day, so check with them if you're interested.
Also, NPR posted the Salvation Army Lassies' Doughnut Recipe on its site in case you're feeling ambitious and don't feel gross about cooking with lard. Happy Doughnut Day!