College student moving to Washington. Unsure on where to live. Best areas for young people?

I am a male 22 year old undergrad student from Boston and I am taking a government job in Arlington for 6 months from Jan-June. I am looking for a furnished room for the 6 months in an apartment/townhouse with other students/interns/young professionals. My main concern is a good social enviornment for younger people, as I will be moving without knowing anyone or with knowledge of the area. I would like to live by the orange line metro, as that is what I will be taking to work. From the reseach I have done, I think I want to live in the capitol or foggy bottom area. Also would live in Arlington, as it would make an easy commute, but would rather be in the city. My budget is somewhat flexible, but would like to stay below $1000 per month for a room. Can anyone offer advise?? Thanks!!