Pasha Bistro, near Dupont Circle, is one of my favorite places to go for lunch. It offers outside seating, so it's also a great place to people watch and get out of the office and into some sun.
The menu is pretty standard Mediterranean food; hummus with pita, Greek salads, falafel, and Gyro's are some of the menu items.
The food is decent, but it's nothing mind blowing. One downside is that the service can be a bit slow. If you're in a hurry, I'd ask for the check as soon as you order.
Pros: Great place for lunch
Cons: Service can be slow