Many veterans of the big band era refer to those years of one-nighters as a "university." Washington has its informal college of jazz instruction and its name is Lettumplay. Founded in 1976 by the late Tony Taylor, the nonprofit facility functions as a training ground for young musicians. Among its alumni are drummer Wynard Harper (now with vocalist Betty Carter), trumpeter Wallace Roney (presently leading his New York group), and alto saxophonist Ron Sutton Jr., now studying with be-bop master Jackie McLean at the University of Hartford.

"Old and New," today's program in Lettumplay's Sunday Jazz Series (4 to 8 p.m. at the Lansburgh Cultural Center, 420 Seventh St. NW), will feature guitarist Lewis Cottom and singer Mary Jefferson, a mainstay on the D.C. jazz scene for three decades. Also on hand will be bassist David Marsh, drummer Tony Addison and keyboardist Malcolm Colbert. Musicians are invited to drop by and sit in.

"I've had responsibilities added on as things went along," says Duke Ellington School of the Arts graduate Cottom of his three years with the Lettumplay Jazz Ensemble, which represented the city last summer at the World's Fair in New Orleans. "This will be sort of like my first coming out as leader where I'll actually have to put things together."

And how does he feel about that? "It's about time!"