Proof is probably the best late-night spot in D.C. D.C. is not a very late city, but Proof is a wonderful late-night spot. The kitchen will stay open late on Fridays and Saturdays. They have great little appetizers, - which is all you need at 12:45 in the morning - and it has a nice selection of wines, and you can go after a basketball or hockey game. It’s small enough to have some atmosphere but big enough to not be packed.