Every Sunday evening, at the Tabard Inn in downtown Washington DC, bassist Victor Dvoskin provides one of the great bargains of the Washington DC jazz scene, an evening of free jazz. No, not three hours of avant-garde expression, three hours of fine jazz music with no cover and no minimum. For the price of a glass of wine or, in my case, a cup of tea, one can sit in the Tabard Inn's lounge and hear Victor, a top-quality bassist, working with a duo with the best local guitarists and/or keyboard p