Until the funding dried up a few years ago, the Sylvan Theater was synonymous with the Bard. But these days the show isn't Shakespeare: It's shake, shimmy and swing.

At 8 each Monday till the end of summer, the Sylvan will be hosting homegrown big bands: the Neophonic Orchestra, the Ambassadors and the Doc Dikeman Band among others, any of whom you'd expect to pay good money to hear.

But this is free, and not just a concert; it has a good beat and you can dance to it.

The other evening, the Mike Crotty Band was holding its own on the stage, which sits in grassy isolation below the Washington Monument. Drums rolling, trumpets raised and saxes full steam ahead, they beat out the daylight with blistering renditions of Thelonius Monk and Scott Joplin, followed up by the likes of Goodman and Miller.

Fifty-odd fans sat tapping toes in the grass. There was plenty of room for blankets and baskets -- even a whole delicatessen, stacked end to end on the ground.

A few joggers-by stopped to listen; a lone couple jitterbugged on the dance floor front and center. After a while they quit, leaving the evening's exertions to a Frisbee- catching dog and the blood-sucking bugs.

"The only dancing I see up here is by a couple of mosquitoes," Crotty said. "We could use about three or four thousand people here," agreed Al Dale, concertmeister for the National Park Service. He said the park service will soon be dousing the knoll with insect spray, the better to welcome a big band of patrons. SYLVAN THEATER -- Big bands, from 8 to 10 every Monday night through the summer, weather permitting.