AROUND 1 O'CLOCK IN THE MORNING ON A SUMMER SATURDAY IN 1983, ONE OF THE hottest stand-up comics in the country finished his last set at a club in Cleveland. In keeping with the Sabbath strictures of his new-found faith, he plunged on foot into the seediest part of downtown, walking for an hour or so past hookers and strip joints and topless bars to the hotel where the club put up its headliners. The club owner cruised alongside him in a car, chatting through the window, remarking on the dangers of the neighborhood. Every now and then, he asked, "Sure you don't want to get in?"

Marc Weiner had never been more sure of anything in his life. Orthodox Jews do not use cars on the Sabbath, and Weiner, a former Hebrew-school cutup who barely squeaked through his bar mitzvah, had fallen in love with Orthodox Judaism. Indeed, the midnight walk was only one in a succession of strange scenes in his life at the time. In dressing rooms in Atlanta or Indianapolis, for instance, he would find himself studying Torah while trying to block out the rhythmic sound of line, laugh, line from the opening act. Stranger scenes and far harder days were to come, as his growing faith would first dismantle his career, then nearly tear his heart in two.

BOISTEROUS ON STAGE, THE 43-YEAR-OLD WEINER -- NOW best known for Weinerville, the brilliantly silly puppet world at the heart of the children's television show "Nickelodeon Weinerville" -- is exquisitely shy in person. Dark and compact, he seats himself yards from a newcomer, listens carefully, speaks hesitantly (and mainly to his lap) and often interrupts what he says to criticize it.

But he loves to perform. Especially, he loves puppets. When he drops to the floor of his small Manhattan office and starts to work his bare fingers across the worn carpet, he almost glows with enthusiasm. (During a recent visit, Weiner -- whose name is pronounced like the hot dog -- was finishing the script for a "Nickelodeon Weinerville" Hanukkah special, to be shown Thursday at 8 P.M. and several times over the weekend.)

"A hand puppet like this, there are human movements there," he says, his practiced fingers bouncing with Olympic precision. "It's doing push-ups. It's sitting. It's crossing its leg. It's flipping the bird." His bare hand, even without benefit of puppet, makes a weirdly convincing human figure. He stands up. Again, he is instantly uneasy as he tries to put into words what excites him about his work. Plagued since childhood by dyslexia, he finds that words often elude him, especially if he thinks about them hard. At last he produces four: "Creating something from nothing."

Weiner's act, back when he was riding the cresting wave of club comedy, was never pure stand-up. He juggled a rubber hand, a toilet plunger and an M&M. He dressed his hand in tiny clothes and walked his fingers over miniature sets, creating a form of puppet he called the Weinerette. Playing a noisy old sea captain in a storm, he doused his audience with water.

It wasn't a particularly subtle act -- Weiner cites Jerry Lewis as a major influence -- but Weiner was going for belly laughs. "He was always very funny, truly funny," says Jerry Seinfeld, who came up through the clubs at about the same time. "And he had a very pure heart on stage. I think people always responded to that."

In 1971, after he dropped out of Monmouth, a small college in West Long Branch, N.J., Weiner had no clear ambitions. He opened a campus coffeehouse he called Expression. He worked as the cook -- and learned to juggle -- on the sloop Clearwater, Pete Seeger's floating ecology lesson. He took a course in clowning and another in mime. By the late 1970's, he was a street clown outside the Metropolitan Museum of Art. One winter night, to get out of the cold, he auditioned at the Improv. Within a year he was a regular.

Early in 1980, he and Rocko, a pugnacious boxer Weinerette with a voice like a pickax, landed a series of spots on "Saturday Night Live." The audience response was fervent, and the exposure catapulted Weiner into the mushrooming club scene. Soon he was headlining all over the country. At first he was thrilled.

"I was just -- Oh, look! Cleveland! A hotel!" He jumps from his chair and takes a goofy, gleeful skip. "You know, I'm coming off a boat."

After a year or two, though, the charms of hotels and traveling began to subside. "The career was really moving nicely," he says, "but I was thinking: 'What am I living for? So I can develop my puppet?' I needed more."

A son and grandson of thoroughly assimilated Jews, Weiner had hardly seen the inside of a synagogue since his bar mitzvah in Mahopac, N.Y., a rustic suburb in Putnam County. The comfortable home he grew up in was only casually Jewish, but now he began to wonder what Judaism had to say about the meaning of life.

To fill the empty hours on the road, some comics go bowling. Some write new material. Weiner began to drop in on synagogues. "I would work Friday night and go to shul Saturday," he says. With his picture on posters all over town, he had an easy time mixing with the congregation. People would often invite him over, feed him, take him in. He went to only Orthodox synagogues, finding a "love for living Judaism" he had not experienced in the congregation he knew growing up.