The White House is probably one of the world's most famous buildings. You can get a free tour if you book a few months in advance, although even from the outside it's a magnificent sight to behold. The U.S. Capitol Building's distinct domed roof presents a perfect photo opportunity. At the Lincoln Memorial, you can walk along the Reflecting Pool and admire the Washington Monument.
As you'd expect in the capital, the range of foods on offer is impressive, with many ethnic cuisines to try, such as at Chinatown. Ethiopian food is particularly popular and well worth trying as it can be hard to come by elsewhere.
Blues clubs are easy to come by in D.C. Check out Georgetown for venues including Blues Alley. Many of the more popular clubs are to be found in the East End of town or on Connecticut Avenue close to the Smithsonian National Zoological Park.
If you're staying for a while, why not check out the day trip destinations? Baltimore is an hour's drive away. Richmond, Virginia is two hours away.