We ended up at the Green Valley book fair, and they were delighted I had tricked them. After picking out books, I strategically loaded them up with some fast food distraction before merging back on to the interstate - north, again. As we were passing a sign that said, "Manassas 10 miles", Pierce asked if we were in back in our hometown yet. Were they ever surprised to find themselves in Northern Virginia!
We had dinner with friends that night and the next day rode the metro in to DC. Our first stop was the International Spy Museum. The boys loved the creepy blue light elevator to get inside. And being able to crawl through the duct work to spy on museum-goers was a huge hit.
There were many hands on activities mixed in with a lot of artifacts and history. The boys liked all the buttons.
There was also a hallway that had a movie of a shark swimming behind glass, and if you touched the glass the shark would attack it, 'breaking it'. I wish I'd gotten it on video the first time this happened. The boys did it over and over and over again. They love being scared or surprised.