One of the amazing things about visiting Mr. Blueberry while he's in Virginia is that DC is very close to where he lives.
I hadn't been to DC since I was 10, which is my opinion is too young to really soak it in. As for our visit, we narrowed our choices to the Natural History Museum and the National Gallery of Art. Mr. Blueberry is a huge fan of evolution and I... well... I can't help but visit the Modern Art section of any museum.
All-in-all some excellent choices in my humble opinion. Although I wish Blueberry could have been there. Too bad they don't allow pets in museums yet.