Years ago we had 2 memorable seafood dinners in the Washington/Maryland/Virgina area-- a crab-bashing dinner in a DC pub and a Friday night seafood buffet in Williamsburg. Are there any restaurants with similar dinners anyone can recommend for an upcoming March weekend?

There are are crabhouses all over the Chesapeake Bay and Potomac River area. There are several good options, depending on where you are going to be spending time and whether you want to eat off picnic tables with papertowels or something more upscale.

Something on the nicer end is Phillip's near the water in DC. http://www.phillipsseafood.com/phillipsflagship/. The food is good, it is by the water and they've got a buffet.

Phillips is OK, but they are leaders in buying foreign crabs for their Chesapeake themed places.

It's not really crab season, but there are plenty of nice crab house out toward Annapolis or in Baltimore. Cantler's is a personal favorite. For good seafood in DC, some favorites are Kinkade's (pricey), Pesce or Johnny's Half Shell.

For a quick treat, the waterfront market in SW Washington is a lot of fun.

The waterfront being Maine Avenue.

Phillips, even the mentioned "flagship" location is very mediocre in my view (and that's being kind). Kinkades is excellent, but very expensive. John Mandis' Market Inn is our personal favorite and also has great steaks. Not much from the outside, but great food and service. Somewhat pricey, but not overly so. Would suggest going on Saturday night when they have the two-piece jazz band.