ROGER MURSICK CAN LAUGH ABOUT HIS comedy debut--now. More than three years ago, he climbed up on the stage at Garvin's Laugh Inn hoping to tell jokes--not become one.

His five minutes on stage seemed like two hours. His mind went blank when somebody yelled, "What --- golf course did you come from?" He didn't get a single laugh. Not a giggle, chuckle or guffaw. The audience sat there, gaping at him like statues on Easter Island.

Mursick was so bad that even the owner of Garvin's couldn't bring himself to watch. He was so bad his wife

burst into tears. Soon after, she left him.

"I bombed--horribly," Mursick says. "I had no delivery, no timing, no material, no nothing. I thought you had to tell the truth up there. I told the truth, and it wasn't funny. It was tragic."

He had every reason never to go near a microphone again, given his disastrous debut. But did that stop him? Hardly.

"There was something I felt right away," he says. "I knew it the minute I got on stage. It was like a shield, a force field surrounding me. One of the other acts said, 'Your stage presence is so refined, you just don't have any material.' I knew then I had to learn everything about the process."

On a Friday night last month, Mursick, 31, a likable dreamer from Silver Spring, paces the walkway between the bar and the stage at Garvin's. He listens to Angela Bofill's "Something About You" on headphones; it helps his timing, he says. He does a few upright push-ups against the wall. Garvin's owner, Harry Monocrusos, a comedy impresario who packs a knife in his boot and a pistol under his leather jacket (fun guy!), has booked Mursick for two 30- minute shows a night, $75 a show, Thursday through Sunday. There are 225 people in the keyed-up crowd.

Emcee Sam Greenfield (His card: "Night clubs, parties, weddings, bar mitzvahs, conventions, concerts, tupperware demos, call 223-1829") finishes a bit and says, "I want to bring up a comic from Washington, D.C., who's had a great amount of success. He recently opened for Warren Zevon; he's opened for the Mamas and the Papas, Frankie Valli and the Four Seasons; he just returned from a very successful engagement in Atlanta, Georgia, and he's here tonight! So let's have a big hand for Mr. Roger Mursick!"

A jazzy fanfare blares from the sound system as Mursick skips onto the makeshift stage, dressed in blue jeans, a suede vest and a white shirt. He swigs from a Heineken and sets it on a piano. The stage is bare and brightly lit. Mursick squints at the crowd as he removes the microphone from its stand. He holds it casually; Garvin's is his back yard. He has a boyish face, hazel eyes, a full head of red razor-cut hair, a dusting of freckles and a dimpled left cheek.

"How about a hand for Sam Greenfield--give Sammy a nice hand," he says. "It's nice to see Sam in men's clothes again."

A monologuist with an aversion to props and zany antics, Mursick covers the same ground night after night. His material is a m,elange of ad-libs, one-liners and comic disquisitions on dating, marriage, involuntary body twitches and old people with hair growing out of their ears. On taxicabs, he muses: "I might be wrong about this, but I don't think there is an American cab driver left in the city of Washington." He jokes that the space shuttle astronauts have discovered what the rings of Saturn are made of: lost airline luggage. Women in romance novels, he notes, all seem to suffer from "burning loins," and every book contains the line, "And then she felt his manhood awaken."

After 3 1/2 years as a professional comic, Mursick has what he considers 45 minutes of solid material; he produces about two minutes' worth of new stuff a month. He presents his routines in the image of a clean-cut, naive guy, an image he carefully cultivates--the better to undermine it, it seems, with a string of X-rated adjectives and a lewd, horror-movie laugh. When he laughs, he can change into a spastic fiend, narrowing his eyes, splaying his fingers and turning a contortionist trick that makes his tongue look like a piece of meat from a side order of antipasto.

If the lines are mostly the same, the performances are different, thanks to the changing tenor of the crowd. White suburbanites are out in force tonight and, at the early show, eager to laugh. The best audiences are usually the ones that gather expressly to see comedy. Once when Mursick was trying to warm up a rock audience before a concert at the Bayou, he was driven from the stage by a bombardment of foil ashtrays.

Comedy is a strangely brutal business. The terminology of failure and success is pure violence: either you knock them dead, or you die. Mursick makes it a practice to reconnoiter his crowds. Subversives lurk in the shadows; would-be hecklers wait to pounce halfway through his act with lines like, "Tell us a joke!"

Mursick once launched his taxicab routine only to be blind-sided by a heckler.

"I took a cab over here tonight from the hotel," he began. "Take it back!" somebody yelled.

"A crowd can smell fear or confidence," Mursick says. "You have to contain them. They want you to take control. If you don't, they'll go for the jugular." Even an audience full of friends is fraught with peril, as Mursick learned when a "friend" starting giving away punch lines as he was setting up his jokes.

Tonight, however, the comic has tamed the beasts, and they are laughing convulsively at his closing anecdote about a blind date with a fat girl. The segment has not always been well received. After one performance, a group of women expressed their appreciation by aiming punches at Mursick's head on their way out. ("I was sitting at the bar, and this herd of pachyderms surrounded me," he recalls.)

"We're not talking about a glandular problem, folks," Mursick is saying. "One pair of the girl's underwear is a full wash load. A big woman we're talking about. Dressed to kill in one pair of hot pink stretch-polyester designer jeans. Designer jeans! There's no signature back here, there's an autobiography. But I'm a gentleman, I ask her where she'd like to go to dinner. She says, 'A&P. Any of the food chains.' I'm a gentleman, I ignore this. I walk her to the car, open the trunk . . ."

And then the emcee is exclaiming, "Roger Mursick, ladies and gentlemen," as the room resounds with applause, whistles and howls of "All right!" Mursick strolls out of the spotlight, threading his way through admirers. Before his weekend run is through, six people will ask for his autograph.

Almost by definition the life of young comics is obsessive. They scrape by, struggling to find a style and persevere through self-doubt, rejection and ashtray attacks in the hope that some combination of luck and talent will catapult them into the limelight.

In the meantime, there are places like Garvin's for aspirants like Roger Mursick. Eddie Murphy played Garvin's before he was plucked from obscurity by the producers of "Saturday Night Live." Joe Piscopo, sportscaster for the hard of hearing, played Garvin's, and so did Sandra Bernhard, the meteor from the new movie "King of Comedy."

Mursick did not set out to chase success as a comic. He grew up in Silver Spring, the second of four brothers, and spent most of his boyhood being shuttled among five foster homes. "Just a childhood with a little deviation," he says. His mother, Nellie H. Mursick, reunited her family after the death of Mursick's father. Roger was in the seventh grade. He didn't have much chance to be funny in school because he dropped out in 10th grade and joined the merchant marine.

"I didn't want to end up on the corner pumping gas the rest of my life, like most of the guys in the neighborhood," he says.

At 17 he enlisted in the Marine Corps and was honorably discharged as a lance corporal in 1971. He drifted back to Silver Spring, where he worked construction and co-owned an interior remodeling business. He earned a high school equivalency diploma and took courses at Montgomery College. But he was restless in college and unsatisfied with his job. He had taken voice and piano lessons and had rapped the drums for 12 years. He was still searching for the performer in him. A week after he was married, his search ended.

"We were married in September 1979," says Alice Patterson, whom Mursick had dated for five years. "The next thing I know, he says, 'I'm going to be a comedian.' I said, 'Are you serious?' He said, 'I'm dead serious.'"

The week before his wedding, Mursick had dropped by Garvin's on open-mike night, when amateurs parade on stage to try their comic gambits. Mursick the prankster, who had found fun in dragging his leg in the Safeway like a troll with a club foot, or muttering loudly outside a bank, "The bomb is set!" and then scampering away, thought, "I can do that!"

He was drawn to comedy, because "it was something I could tackle by myself," he says. "Win or lose, I'm on my own up there."

It was also a kind of redemption for a man who, says his wife, "has a brick wall around him." In comedy, the Mursick the loner found a communal sense that escaped him in foster homes.

"I never felt accepted," he says. "It's the typical sad sack story of most comics. On stage, I'm willing to expose myself . . . Comedy is very intimate. I love that. You're open. You can touch the audience. You can tamper with their heads. They allow you to reach them."

With the fiasco of his debut fresh in her mind, Mursick's wife thought comedy might make a nice hobby for her husband. But was it possible for him to make a living by dying on stage?

Mursick could not be dissuaded. He immersed himself in the pursuit of funniness. He bought Official Bedroom Joke Book, Woody Allen's Being Funny, and, to brush up on weirdness, The World of Franz Kafka. He drove to Garvin's four and five nights a week to watch comics perform. He bought tapes of George Carlin, Groucho Marx and Bill Cosby. On the back of matchbooks and napkins and various paper scraps, he scribbled notes for jokes. He ran through his act for mirrors and tape recorders and any consenting ear. He took to heart the advice of another comic who told him to "draw out the irony" in his jokes. He learned to embroider the truth and to lie like a Watergate conspirator.

After six months, his wife had had enough. Her husband hadn't noticed the pink eviction notice tacked to their front door. He wasn't bringing in any money (they lived on her paycheck), bills were piling up, and he didn't pay any attention to her unless he was trying out a new routine. She packed up the furniture and left.

The separation lasted a week. Mursick pledged he would mind responsibilities, and she returned. Still it was a difficult time. Mursick felt the pressures society seems to place on a man in his late 20s to grow up, hold a steady job and get . . . serious. He saw a psychiatrist. Inevitably, he tried out his routines on the shrink, who reacted indifferently. He stopped going when "I realized I was as normal as anybody else, except that I was doing what I really wanted to do."

It took Mursick two years to get funny, he says. After bad nights, he took solace watching movies, playing tennis and working on his routines. He developed at Garvin's, much to the pride of owner Monocrusos, who now says Mursick is "the best young comic in Washington."

It was two years before Mursick was good enough to earn $50 a night as a regular emcee at Garvin's. When his jokes weren't funny, he made a little money doing carpentry at the club. He built the loft and the sound booth. In December '81, he got his first paycheck as a feature act opening for Frankie Valli and the Four Seasons in Baltimore: $350 for a 40-minute performance before 6,000 people.

About eight months ago, he says he achieved a breakthrough when he stopped "monitoring" himself and went with whatever entered his head. He says he felt an electrifying sense of spontaneity and freedom, and the first stirrings of a comic identity.

"Most every young comedian says, 'I have to get my own signature.' You search for so long trying to get that character until you come full circle and what comes out is yourselfs. That's the character --you."

Today Roger Mursick makes about $500 in an average four-day week; he works about 15 days a month, and travels in his four-wheel drive Chevy truck, a remnant of his life in the construction business. His resume traces the path of many aspiring comics on the east coast: a circuitous journey from The Punch Line in Atlanta to Catch A Rising Star in New York and the Comedy Works in Philadelphia. He talks shop, discussing the new acts, bad crowds, big breaks and the politics of success.

He wants to be good enough to attract an agent, good enough to buy a cassette of Roger Mursick's comedy, like the cassettes of George Carlin and Groucho Marx stacked above the stereo in his living room. He wants it all--"the Capital Centre filled with 25,000 people there to see him," says his wife. In his grand fantasy, Mursick imagines fame, wealth and a mark on the world: "I wouldn't mind a few horses, a nice little Porsche and a house in upstate Connecticut or Southern California," he says. "I'd like to break comedy ground, and 10 or 15 years down the road, I'd like to have young acts listening to my tapes and learning from them the way I'm learning from other comics."

He spends six hours a day at home, foraging for ideas in newspapers and magazines. He sends out videotapes of his act and spends $100 a month on phone bills, hustling up jobs. He fills pages of legal pads with sketches and notes for jokes. He works at his profession like a baseball pitcher perfecting his game, learning to change speeds, control the fastball and break the big curve.

In the morning, just to get out of the house, Mursick stops by a Hot Shoppes on Rockville Pike for breakfast. Evenings are given to back- stage booths in comedy clubs. Trying a new joke, a new routine, he still gets dry in the mouth and wet under the arms. He comes home late, and flops on the downstairs couch in front of the television to watch comics on Johnny Carson or David Letterman. He often falls asleep there, long after midnight, dreaming someday soon . . .