What to do in an afternoon in D.C.

I have to go to the district in early March for work and will be in the Crystal City area of VA. My meeting should be over by 11 AM and my flight doesn't depart Reagan until 8 PM. Haven't been to D.C. in a long time and need to tool around for several hours what would you do?  FWIW I'll be accompanied by a female co-worker so it needs to be friendly to the ladies.  My boss suggested the spy museum and that sounds really interesting, but if there is something you would endorse I would love to hear it.

I have enjoyed the National Air & Space Museum when I have visited DC.  The collection they have is absolutely amazing - everything from the Wright Flyer to The Spirit of St. Louis to an actual V-2 rocket.

Looks like it is about 15 minutes from Crystal City to the museum on public transit.

Yup definitely some amazing museums there. Spy museum is cool 

I'll 2nd the Air and Space Museum. SWMBO and I walked out of there thinking we had spent maybe 3 hours in the museum, when in reality it had been nearly 7! Fascinating stuff, could easily have gone back and spent the whole next day there as well. I need to get out to the other location near Dulles one of these days too.

IIRC, Reagan is maybe a 20 or 30 min ride on the metro from that area. 

There are tons of great museums in DC, pick one according to your interests.  The Smithsonian has multiple great art museums (I'm partial to the Freer and Sackler galleries), and I hear the Musuem of American History is great too.  Last time I was at the spy museum I think I was through in about 2.5 to 3 hours.  If you're a news junkie I've heard great things about the Newseum, and the National Building Museum is also on my list for someday.

Any of the museums would be a good choice. 

Pick the museum of your choice. Hard part would be keeping to a schedule to catch your flight. Also, Zoo, but last I knew it was a hike there from the nearest metro station. 

Lastly, how much luggage will you be carrying around?

The zoo is about a 10-minute walk from the nearest metro station (it's basically dead center between two stops). Would also be a long ride from there back to DCA so probably not a great idea for the mentioned time frame.  With more time though, definitely worth a visit.

The Air and Space Museum was already on my radar as the office I work in had a recent impact on one of the exhibits. It would be nice to show our workers the impact of our work.

As an aside I've been told to visit the gift shop at the really big office building we will be at for work. Probably won't do the tour though.

As to baggage, hopefully I will just have a backpack. I'm going to try and send our work material back with our military presence.

Yeah, just ride Metro to the Smithsonian stop and check out the mall.  Be warned, you lose your sense of scale there.  You might think that it's not too far from the Capitol building to the Washington Monument, but it's a long walk.  Especially when you're drunk on a Sunday night.  But I digress...

Or go to the Mall and visit the various monuments of our history.

I always wanted to go back and see how many pictures I could get of things I recognize from fallout 3 lol