It must be dumb luck, says Irving Kruger to himself, and to everyone within earshot. And with his booming New York baritone, that is quite a few people.

It was just plain, good old-fashioned dumb luck that high-stepping Gloria De Brunner, whose jitterbug swing recalled the glory days of the Savoy Ballroom, wanted him as a dance partner.

It isn't that Kruger doesn't have chops. He was a jokester, a raconteur and an entrepreneur. ("I was self-employed. My boss was rotten.")

It's just that Irving Kruger doesn't think of himself as a hoofer, really. But there he is, 82 years old, giggling with embarrassed glee, as he tries to match footwork with the graceful De Brunner during a practice run of "Rock Around the Clock."

"It's hard to keep up with all the spring chickens," says Kruger.

The truth is most 20-something lindy-hoppers couldn't swap steps with the 72-year-old De Brunner. But the dancer's ebullient energy is par for the course among the Montefiore Follies performance troupe — a veritable "Cocoon" sprung to life in the dining room at the Jewish Community Center of San Francisco.

The troupe, which has been around for more than 20 years, performs everything from Gershwin to Yiddish favorites to "My Fair Lady," about 12 times a year. Many of those performances take place in front of other seniors, including residents of the Jewish Home and other facilities.

Kruger is the troupe's one-man Greek chorus, providing anecdotes and personal histories to match every performance. He's been performing with the Follies for more than 20 years, longer than anyone except Richard Koldewyn, the group's irrepressible pianist and director.

Kruger's recollections are cut short by the arrival of Julius Drabkin, sauntering to the tune of "Just a Gigolo."

"This guy's real cosmopolitan," says Kruger. "We try to get him to do all the international stuff."

Indeed, Drabkin is nothing if not suave. With his granite jaw, slicked-back pompadour, red bowler tie, gray cardigan and perfectly pressed slacks, Drabkin is a ringer for Louis Prima.

The Latvian-born Drabkin, 83, can sing in Russian, German, Yiddish and a little French. He sings Yves Montand and Maurice Chevalier standards. He is also a Holocaust survivor who lost 27 members of his extended family in the camps.

Drabkin struts across the stage, crooning "everywhere I go, people say the same things about me…" Koldewyn, from behind the piano, urges him "to get sexy out there."

Sexy is not a problem for the aptly named Valentine Ginokov, 72. Ginokov, who's long, flowing gray hair and energy recalls Anthony Quinn, speaks almost no English. He immigrated to San Francisco just seven months ago, and Drabkin translates instructions to him.

But language barriers don't dissuade Ginokov from belting out Russian tunes, or showing some moves that combine classical Russian ballet with the NFL touchdown victory-dance moves. Ginokov is so on fire that several Russian women watching the rehearsal start to titter among themselves, nodding appreciatively.

He's so on fire, in fact, that he can't stop. When his number is up, he is still pacing back stage, shaking his head, as if to say, "I didn't nail that last step like I wanted to." It seems the only way Ginokov can control the creative fires raging within is to hug other cast members — which he does constantly.

And the guy he's hugging now looks vaguely familiar. It's none other than Larry Ching, the 80-year-old former star of San Francisco's legendary "Forbidden City." The man with the velvet pipes, about whom Herb Caen once said, "Frank Sinatra is really the Italian Larry Ching."

Ching, whose performance heyday was in the 1940s and '50s, is sharing the stage with the group's other main songbird, Jackie Soufi, 74. They do an ensemble version of "Puttin' On the Ritz," complete with top hats and canes. Chorus members Pauline Raven (an English singer with a new CD out), Ruth Tobin and Jeanne Burke keep the tempo as the duo reach a crescendo.

The final number, fittingly, is from "Fiddler on the Roof." Out comes the suave Drabkin, exhorting the audience to soak up all of life's minor joys and heartaches.

"To life!" shouts Drabkin.

"Louder!" exhorts Koldewyn.

"To life!! L'chaim!" bellows Drabkin, and there is no doubt that he really, truly, feels it.