Well, I have to say that the trip to the Smithsonian was awesome. We made it down in about 3 and a half hours, found a parking spot, and walked to the Museum of Natural history in under 15 minutes. My older son is a dinosaur geek so he didn't even need to read the plaques. He knew the dinosaurs and their info. On to the Air and Space Museum, where they had everything from the various Apollo rockets, part of the " Space race "; to the Wright Brothers airplane. It was all good. After that we went over to Virginia, we passed the Vietnam Memorial along the way, we were pressed for time so we didn't stop. There's a part of the Smithsonian in Chantilly, Virginia known as "The Hanger". For me that was the best part. They had everything from World War II aircraft(F4-U Corsair) to the most modern fighters (F-35), and of course they had the SR-71. That's "Jetfire" from the last Transformers movie. We saw the space shuttle Enterprise, the Enola Gay. You name it; they had it. I was impressed. At one point, I rattled off the names of about twenty aircraft. I looked at my wife and told her; Yes, there is a whole other level of geek you never knew about......lol If you park on the street during the weekend, parking is free. The museums other than "The Hanger" are free; The Hanger was $15. We packed breakfast and lunch; We did stop for dinner, and gas and tolls totalled about $50. All in all, not too expensive. I would also recommend a map of the city/museums. It's much easier to navigate.