I'm visiting relatives in Maryland at the moment.
Yesterday, since I can't just sit in a house all day, I took my daughter into Washington D.C. and we did the tourist thing and walked around the Mall a bit in the wonderful 50+ F weather and then spent a little time in the Smithsonian's Museum of Natural History. When I asked my nine-year-old daughter what area she wanted to see, she said "ancient sea life" so we looked at fossils of trilobites, crinoids, brachiopods, eurypterids, mollusks, etc. We also looked at Burgess Shale fossils and she knew the name of a lot of them (opabinia, anomalocaris, etc). From there we went upstairs to see the mineral gallery, skipped the gemstones where everyone else goes and instead gawked at the beautiful mineral specimens (I'm so proud of her, she likes fossils and minerals).
Then we walked up to Chinatown for lunch, found a little gelato place for desert, and then walked back down to the Mall and around the Capital building (we took a tour there last year). Then up to Union Station to see the train set they have set up there and the metro back to the father-in-law's house.
A good day.