I suspect it is a national or semi-
national chain, as there are also a couple of these in
Birmingham, Alabama. On is at
Five Points South, the other at The
Summit. They serve
nifty fountain drinks like
cherry Coke (with real
cherry syrup) or (my
personal favorite),
Vanilla Dr. Pepper. (Good
milkshakes, too!)
The atmosphere is similar to Steak 'n Shake, if you happen to have one of those available for comparison (but unfortunately, not open 24 hours).
I don't know about the ones in the D.C. area, but at the ones down here, if anybody plays "My Kind of Town" by Frank Sinatra, the whole staff drops what they're doing for a moment to lip-sync along with the ketchup bottle. (Cute choreography, too!)