1. United States Capitol
One fixture you can still access in post-9/11 Washington is the Capitol, and it is a weird and beautiful place. There are 540 rooms and almost as many lawmakers, all connected by winding halls, tunnels and an underground train. To get inside, you have two choices: You can go on an official tour after getting tickets from a kiosk just outside the building or you can contact your state Senator or Representative to get a pass to the gallery and watch the place in action — or inaction, which is equally interesting.
For lunch and politico-spotting, crash one of the surprisingly decent, low-priced cafeterias in the Rayburn House Office Building or the Longworth House Office Building on Independence Avenue, or get a glass of wine and pasta at the upscale Sonoma on Pennsylvania Avenue, right behind the Library of Congress. (Metro: orange or blue line to Federal Center SW)