Happy National Donut Day! In celebration, Dunkin’ Donuts is offering guests a free classic donut today with the purchase of any beverage! Need a drink suggestion? Try Butter Pecan, Cookie Dough and Pistachio flavored coffees- all back on Dunkin’ Donuts’ menu for the summer! Dunkin’ is also introducing new Frozen Lemonade available in Original and Strawberry. Both flavors are made with real fruit juice for simple and pure frozen refreshment.