Did some museum time over the weekend.
The Air & Space Museum has "A New Moon Rises" - it's temporary, but there's no formal closing date. It has some amazing pictures of the Moon taken by the Lunar Reconnaissance Orbiter. (Yes, you can see them online, but...) Capitol end of the museum, upper floor on the right.
The American History has "Fantastic Worlds" through February 26, 2017. It's an exhibit of the intersection of science and science fiction in the Victorian era that features very little from America - but it's worth checking out, especially if you're interested in steampunk.