Lobster Shack in Greenpoint
I think it's The Lobster Joint...? In any case, we liked it. Hectic atmosphere, but the staff was very on top of things. We had a lobster roll ($17 for a healthy amount of seafood with a huge serving of fries and a cup of coleslaw), a clam roll ($14; proper belly clams, with the same sides) and excellent Beausoleil oysters (forget the exact price but they were less than $3/each). I think it's a great addition to the area.
1073 Manhattan Ave, Brooklyn, NY 11222