THERE'S SOMETHING FUNNY going on at Arena Stage. Just about the only sound you hear in the Kreeger Theater is the sound of an audience laughing.

And chuckling, snorting, gasping . . . Nonstop.

Silent comic/juggler/mime/pickpocket Avner Eisenberg, a one-man Marx Brothers who calls himself "Avner the Eccentric," is launching his national tour with a four-week stand at Arena.

Wait, "stand" is definitely the wrong word.

In a lightning-quick two-hour schtick, Avner prankishly plays with everything within reach: ropes and roses, peacock feathers, toilet paper, his tongue, his food -- and his audience. Only good sports should sit in the front rows, as Avner freely plucks his "props" from their ringside seats.

But there's nothing to fear. There's not a mean bone in his body -- in fact, there's often reaon to doubt there are any bones in his body (apart from the obvious funny bone). Sweet-natured Avner makes sure everyone looks good (if silly) in his improvisations.

Avner is often counted in the roster of the "new vaudevillians," which includes the lunatic Flying Karamazov Brothers, the Big Apple Circus, Paul Zaloom and Bill Irwin (who will appear at Arena later this season). Complete with the classic clown's bulbous red nose, baggy pants and his own shy, sheepish grin, Avner displays an encyclopedic memory for every low-comedy slapstick stunt, from the crudities of the class cutup to the more elevated arts of juggling and mime.

And he's easygoing -- if a gag works, great. If he flubs it, all the better. He gets high marks for versatility and alertness to the audience -- one of the evening's funniest moments comes when Avner "orchestrates" his own ovation.

You get the feeling that if Avner stayed on at Arena, he could rival even Stephen Wade's long-run record with "Banjo Dancing."

And though Avner's show is speechless, keep an ear open -- half the fun is listening to those laughable laughs erupting from the audience.

AVNER THE ECCENTRIC -- At Arena Stage's Kreeger Theater through October 6.