One oddity about DC is the total lack of inexpensive, fast casual restaurants that are open for dinner. I work long hours, and if I get home late and don't want to cook, there seem to be almost no options for an inexpensive, decent looking dinner that isn't from McDonalds or a shady Chinese hole-in-the-wall that also serves chicken wings. Being from California, I'm accustomed to a wide variety of eateries at every price point, but I feel like in DC, while there's incredible fine dining, there's almost nothing mid-range.
Here's the few places that I know. Please let me know if you have any others to add to the list: