To echo what people have said here, see the monuments. Even though the Washington is surrounded in scaffolding, it looks pretty cool when it is lit up at night.
As for restaurants, I'd say go to Old Town Alexandria to get a lot of decent food. For bars and what not it depends where you are staying as there has been weekend track maintenance on almost all tracks every weekend for well over a year. Personally I prefer Bethesda or Old town for bars just because if I ever need a ride back from someone, either of those places aren't complete hell to get to via park/highway at night.
As for restaurants, I'd say go to Old Town Alexandria to get a lot of decent food. For bars and what not it depends where you are staying as there has been weekend track maintenance on almost all tracks every weekend for well over a year. Personally I prefer Bethesda or Old town for bars just because if I ever need a ride back from someone, either of those places aren't complete hell to get to via park/highway at night.