If you like modern art, you have to go to the Renwick Museum. It is just in front of the White House, and it has reopened a few months ago. The “Wonder” exhibition is great, with very visual and large-scale pieces from nine leading contemporary artists. It closes in May. I love this “Plexus A1” rainbow of Gabriel Dawe, I also love the trees of Patrick Dougherty. My favorite piece is the colored net by Janet Echelman.
You can hear Janet Echelman a few years ago in a TED conference about imagination:
Paris - Washington DC 