Another word of caution for anyone who doesn't use subways frequently. You have to buy a seperate pass for each person.

By mistake, I have bought one pass for my family and put the $ amount for all of us to travel on that one card. You would not BELIEVE what a hassle this is for the station managers to try to undo. It's amazing. And I've done it TWICE - they should bar me from the subway!

Also, regarding the metro - you feed the card in but you need to retrieve it to go out! So don't forget where you've put it.

The all day metro pass is good after 9:30 and is now $6. Grab a subway map from the station manager. It's really easy to get around and saves from the hassle of dealing with parking.

NOTE: Some of the metro parking lots fill up very early in the morning (the lot I go to fills up by 7am). Ask your hotel for advice about this since I'm pretty sure the stations in Falls Church are also tricky to get parking. Another tip: if the lots have "reserved parking" spaces, get there about 9:50am. They're fair game for anyone to park in after 10am (if you wait until 10:05, you're probably going to be too late).