Okay, so you're smart enough not to drive in Washington D.C. And you're even smarter not to get caught in the infamous Dupont Circle. Then, tie your shoe laces. There are so many wonderful shops and restaurants to check out in the Dupont Circle area. Just remember, when you're taking the metro, you want to get out of exit 3 (the really long escalator) to walk right into the main area.
All the streets that converge into the dupont circle are a great place to go out at night. All the area is full of restaurants, bars and other places to party. The atmosphere is so cool and fun. If you are looking for THE gay area of Washington, this is the one but I recommend it to all publics ;)