For a seafood buffet, try Phillips Seafood. You'll get an ample supply of very nice seafood preparations, snow crab legs, steamed clams, shrimp with Old Bay seasoning, etc. All of this plus dessert for about $25 each, drinks are extra.

For a cheaper, and more local spot, try Ben's Chili Bowl in the U Street Area- famous shakes as well.

Near GWU, try The Burro for some cheap and excellent Mexican food.