Though pretty famous in Boston, I heartily recommend that visitors try the No Name Restaraunt at 15-1/2
Fish Pier. Cash only. Rarer than rare in Boston, ample free parking. Simply honest and fresher than fresh local sea food, including the local fish "chowda", which is much thinner than what passes for clam chowder most anywhere else. Order the fried clams and get what is probably the definitive item. Even the fries are just perfect. Wine and Beer. The place generally caters to fisherman, construction workers and others of large appetite. As unfancy as it gets. Nothing trendy here, and I suspect it is any Chowhound's choice. Enjoy!