Join the Dunkin’ Donuts Perks Program to get a free medium Dunkin’ Donuts beverage of your choice and another on for your birthday. This particular sign-up form is through Facebook, although this is a promotion that has always existed and can also be accessed through their website. If you are already a Perks member, it won’t let you sign-up again.
One note – If you are signing up for the first time, make sure to allow “news and special offers” or they won’t send you your freebie!