The National Center for Emerging Technologies, part of the Academy for Educational Development (AED), is located at 1825 Connecticut Avenue NW in Washington DC. The nearest Metro stop is Dupont Circle on the red line. From the Dupont Circle Metro, walk up the hill (north) on Connecticut to 1825. The National Center is on the 1st floor;, the temporary sign says "AED's Technology Lab" (the Center has just moved).
Driving from Virginia, your best bet is to take Roosevelt Bridge (most direct access is from Route 66 or Route 50) to 23rd Street. Take 23rd to George Washington Circle. Go around the circle to 22nd Street, which is one-way going north. (If you're really familiar with the city there are a number of shortcuts to 22nd, rather than going up 23rd.) After you cross Massachusetts Ave. (4-5 blocks), you get on Florida by taking the slight right (comes in at about 1:00) Florida crosses Connecticut in about 4 blocks. There's a garage (in our building) on Florida shortly after you cross Connecticut, and there's street parking if you're lucky.