A new name has appeared alongside the small handful of late-night restaurants open after shows in downtown Washington D.C. It used to be that the Old Ebbitt Grill and the Kramerbooks restaurant were the only places folks knew of to bathe in the afterglow of a great show or concert downtown. Lately that has changed, with the inclusion of the Bistrot du Coin in a recent survey of the three “Best Late Night Restaurants” in a prominent regional monthly magazine.