SPY MUSEUM. OMG. I've been trying to make time to go there because of the Operation Spy thingy, but I haven't been able to. It costs money, but I've heard that it's totes worth it.

The History is awesome, but I don't think you'll have time to miss it. The Holocaust Museum is amazing - very moving but also very, very educational, even if you already know a lot about the events. The National Portrait Gallery and National Archives are both pretty cool.

Did you know you can call your congresspersons's office and their staff will give you a free tour of the Capitol, including the fun underground passageways and a look at the House and Senate chambers and the original Supreme Court office? Your tax dollars at work! We did it a couple years ago and it was great.

Also, visit the monuments at night. Lots of walking but very impressive, especially the Lincoln.

Seconding the National Portrait Gallery, which is in the same building as the Smithsonian American Art museum, and they're both very very cool.

American History is closed but I remember that they had a backup exhibit of the most popular artifacts (like Dorothy's ruby slippers and Mary Todd Lincoln's inaugural gown) in a gallery at the Air and Space Museum.

If you like gardens, be sure to check out the Haupt Garden behind the Castle and the Ripley Garden behind the Hirshhorn -- where I proposed to my wife! And Bartholdy Park behind the Botanic Garden is great for smalltime birding.

Also get to Georgetown and try the canal boat ride.

You might consider taking the Metro up to Capitol South, and popping into the Great Hall at the Library of Congress, in the Thomas Jefferson building. It's pretty impressive, and has a great view of the Capitol from the front steps.

The Folger Shakespeare Library is right around the corner, too!

The National Museum of the American Indian is relatively small-scale compared to the others, but is free as it's part of the Smithsonian, and has a great variety of amazing objects still managed, I think, by the tribes from which they were borrowed. It's something you could see in a morning or an afternoon, and their restaurant downstairs features well-prepared, tasty, all indigenous-to-the-Americas food. It's a good stop for lunch if you're over there.

The Lincoln Memorial at night is positively haunting.

Seconding mdonley about the food at the NMotAI. nom nom nom. And the museum is good, too.

You might consider taking the Metro up to Capitol South, and popping into the Great Hall at the Library of Congress, in the Thomas Jefferson building. It's pretty impressive, and has a great view of the Capitol from the front steps.

Nah, all the cool kids work in the Madison Bulding. My mom's in town this weekend, and my daughter is performing at the the freakin' 9:30 club, or I'd offer you a behind-the-scenes tour. Are you still going to be here Monday?

Go to the Hirschhorn.
Go to the Hirschhorn.
Go to the Hirschhorn.

i wish i could go to the Hirschhorn.

And the Women's Museum.

And the National Gallery.

You also used to be able to call your Congressperson and request a pass to the viewing gallery for the House or Senate. I second the National Gallery!

You can view the House gallery, but not the Senate--both chambers are out of session until September, and the Senate closes their gallery during recess. And, yes, you'll need to get a pass from your Member office. Even without the gallery pass, the tour is pretty good. You can find info about that on the House site.

Second the Jefferson building - I'd forgotten how awe-inspiring that is. They do free tours - the info desk can fill you in. And also recommending any mrmoonpie-related experiences or recommendations!