Monday nights are possibly the most dreary of the week, even in a Fort-sized city. But jazz lovers – and those with a keen interest in learning more about this passionate, intricate, oddball, and romantic American musical form – should mark their calendars for this Monday April 20. Jubilee Theatre is hosting an evening called “One for Duke” at Scat Jazz Lounge in Sundance Square. Jubilee’s in-house composer and instrumentalist Joe Rogers serves as m.c. and personally selects the tunes for this casual showcase of famous standards and more obscure gems from Duke Ellington’s vault of material. Rogers will be playing with his trio and a few invited musician friends. A cash bar will be open. Also, there’s a general call for professional musicians fluent in Ellingtonia to show up and jam with the program. If all the stars align, this will turn into an old-fashioned jam session – which means the gorgeous noodling could extend past many nine-to-fivers’ bedtimes. Of course, the admission price includes the right to come and go as you please during the performances. This reflects the Duke’s own wry, laid-back attitude about his music: “I merely took the energy it takes to pout, and then wrote some blues.”