Open from the end of February to the end of November, Sullivan’s on Castle Island is a Boston institution. It first opened in 1951—when hot dogs cost 15 cents—in an aluminum shack with pull-down shutters. In the late ’80s it moved to its current brick building, which is a replica of the officer’s quarters that were situated bayside in the early 1800s. A concession-stand-like operation, Sullivan’s draws big crowds, but the line does move relatively quickly. The food menu is a mix of New England classics (lobster rolls, fried clam strips), breakfast sandwiches, burgers, dogs, and fries. And far from an afterthought, the ice cream menu has its own devoted following. The soft-serve is standout, and the specialty, called the Razzle, is a whipped soft-serve with your choice of Oreos, M&Ms, Reese’s, Snickers, or chocolate chip cookie dough. They also have Hood ice cream and Richie’s Italian ice on stock.