Or any other wildly fun thing to do within driving distance of DC?

DC Slap 'N Tickle?

Virginia Beach is about 4 hours driving for us in Columbia, and pretty easy to get to. You just head south on I-95, then east on I-64, and that ends at Atlantic Ave (one of the main streets in VA Beach, which is parallel to the boardwalk).

Baltimore has a very nice aquarium, and the inner harbor offers a number of things to do, like tour a WWII diesel submarine, tour the USS Constellation (one of the oldest Navy ships still afloat), or spend a few hours renting paddle boats.

Or if you're into amusement parks:
1. Six Flags is just east of DC.
2. There's a Kings Dominion in Doswell, VA, which is about 2.5/3 hours south of DC (straight down I-95).
3. Or there's Busch Gardens/Water Country, Williamsburg, down near VA Beach (same directions as above and you pass it).

Anyway, if you're heading up here on a Sunday/Monday, post it up. I'm sure a number of us could meet up for a lunch or something while you're up here.

Duck beach / Outer Banks, an hour south of Virginia Beach is a gem. Head and shoulders above just about any other beach on the east coast outside of florida. It's about 5 hours out from DC if you can avoid the high traffic days (friday - sunday) and it is friggin beautiful. Can't recommend this place enough. Kitty Hawk is there, where the Wright Brothers first flew, they have a couple hundred foot high sand dune, and beach rentals for every price point you're looking at. It's relatively quite, with the best waves on the East Coast.

You and the misses would enjoy doing a tour of virginia wineries. You'll start finding them about an hour west of DC, heading out Rt 66, and it's in some incredible countryside. Horse country, rolling hills with mountains in the distance. There are some great hiking trails in the Shenandoah Valley as well. Old Rag Mountain is a tough trail climb with lots of bouldering (probably take your family 7 hours to do the full circuit trail), but my wife and I enjoy it. Don't plan anything strenous for the next day if you plan to do it. Also out in the Virginia Countryside you'll find Skyline Cavers and Lurray Caverns, some neat underground caves with guided tours. Lurray I think has a cave set up where they've attached strikers on various stalactites in a cave so that someone can play music by conducting the strikers to hit their variously pitched stalactites. It's fun.

If you're looking for the closest beach to DC, I'd recommend Sandy Run Regional Park. It's about 45 minutes east of DC, by the Bay Bridge going over the Chesapeake Bay. They've imported sand to make a well groomed beach there, they have showers and bathrooms, they have concessions, and picknicking areas, as well as boat launches and other park areas for baseball and other sports. When we want to take a fun day trip we usually head there. Across the bay bridge you can find several different places to eat a great crab dinner to finish off your day.

Another activity people do is White Water Rafting in West Virginia. It's about 3-4 hours outside of DC, but they have resorts in West VA that do the White Water Rafting, bike rides, hiking, rock climbing, and hot spring spas. I haven't been myself, but no others who've enjoyed that sort of thing. Just watch out for the banjos.

Baltimore Acquarium and the Inner Harbor of Baltimore or both great sites to see, another fun day trip.

lol you had the percentages on your side, but she's actually the misses

D'oh! Apologies. I had mixed together a few "Rabhattans" and gotten sloppy.

Enjoy your trip to DC!

Outer Banks gets my vote as well. While VA Beach is closer to where I live, I got married on the beach in the Outer Banks because we like the atmosphere better down there. Plus you can find some fairly empty beach space down there without needing too much 'local' knowledge compared to the others (VA Beach, Ocean City MD) in my experience. Just drive a bit north or south and civilization thins out.

That'd be called Jockey's Ridge, in case you're wondering.

I prefer Outer Banks, NC for the atmosphere, but I usually go to VA Beach since I have relatives there. VA Beach has some really nice non touristy beaches if you know where to go.

Rehoboth and Dewey Beaches (DE) are also nice, and not too far from DC (much closer than the others). Dewey Beach is a yuppie party beach. Ocean City is very touristy (concrete jungle). Lewes and Bethany Beaches (DE) are quieter, much like the Outer Banks. (I grew up in the Rehoboth area (Lewes) FWIW.)

Busch Gardens is a nice theme park. But don't forget it's sister park - Water Country USA. You can get a pass to do both. It's an hour west of VA Beach, and would be a good way to liven up a beach week.

I went to Worcester, actually, but my sisters went to Cape. You from the area?

There is so much to do within 3 hours of DC, it will be difficult to pick. For a bike riding, camping, beach goodness Cape Henelopen in Delaware is always a good time. You can also catch the Cape May Ferry over to Cape May, New Jersey. Our family prefers the Delaware beaches as being a little less rowdy than the Maryland beaches. If you want to see the Ponies though, go to Ocean City, Maryland and out to Assateague Island. Remember, the ponies are wild. The do bite and kick.

Who's up for a Slap and Tickle when they are in town?

So biting and kicking ponies made you think about having a GWJer slap and tickle?