The teenage playwrights arrived in New York knowing that Alfred Uhry would invite them over for Chinese food and that Stephen Sondheim would drop in on them during their stay. Such heady meetings generated much anticipation among the winners of the 24th annual Young Playwrights Festival – none of whom were old enough to buy their own beer. But when Mr. Sondheim met them at dinner earlier this month with Bernadette Peters in tow, and Ms. Peters treated them to renditions of “Broadway Baby” and “Children and Art,” the young playwrights were thoroughly dazzled.

The next day, however, they were back at rehearsal, for it is the policy of the Young Playwrights Festival to dole out a pound of real-world grit with every ounce of glamour. The festival, launched by Mr. Sondheim in 1981, does not talk down to its writers, who are all under the age of 19 when they submit their plays. Young Playwrights believes in treating its winners as theater professionals.

Thus they face and deal with rejection: Out of 1200 submissions in the last competition, only 10 winners were chosen (though all entrants receive a page of thoughtful comments). Thus the winners are brought (all expenses paid) to New York, where they stay in a hotel and see plays while honing their craft in an intensive 10-day workshop stocked with professional directors, dramaturges, and actors. They learned firsthand how hard it is to get a play produced in New York: This season, only three of the winning plays were chosen for the big prize – a fully-funded professional off-Broadway production.

It was the notion of producing young writers’ work that first intrigued Mr. Sondheim back in the 1960s, as he sat reading an advertisement in the London Sunday Observer describing a similar competition for young Brits, culminating in a spring production at the Royal Court. Since the festival’s founding, however, the cost of producing plays has climbed steadily. This season’s 21 performances at Playwrights Horizons’ cozy Peter J. Sharp Theater will run from May 9-27 and cost approximately $200,000.

Yet having the playwrights see their work up on stage – complete with sound, lighting, and costumes – has always been critical to supporters like the late Wendy Wasserstein, a board member for over 20 years. “Wendy used to say, ‘Everybody gets a reading, everybody gets a workshop. But where you really learn is in production,'”Young Playwrights artistic director, Sheri Goldhirsch, recalls.

It’s an eye-opening experience even for relative theater sophisticates like 20-year-old Deborah Yarchun of Austin, Texas, whose experimental drama “Freeze Frame,” is on the festival bill. Her high school’s extensive theater program offered 30 productions a year and annual trips to New York to see plays, and Ms. Yarchun spent hours reading plays from the program director’s vast library. (Her favorites: Peter Shaffer, Doug Wright, and Tony Kushner, “who revolutionized my writing by showing me you could have split scenes.”) But having her play staged on 42nd Street – by professional director Richard Caliban, with a cast of Equity actors – is what Ms.Yarchun calls “the most amazing chance you can be offered as a young writer.”

Through casting and rehearsals, design meetings and tech run-throughs, Ms.Yarchun sat at Mr. Caliban’s side – a professional writer on a Dramatists Guild contract, just doing her job. “It’s really hard because sometimes people interpret your work differently than you do,” Ms.Yarchun said. “The hardest moment for me was during the tech week, when they were making big decisions and I wanted more input than what I actually had as the playwright. I had to learn to carry myself professionally and leave the room at one point rather than say,’I don’t like that decision’ at that exact moment.”

Later, sitting through the technical run-through of her dark multimedia drama, Ms. Yarchun noticed that some of the cues were off. “Very nerve-racking,” she said. But there was still a little more time to tinker, and by the night of the first preview, it was all working. “Some of the actors are really dead-on for their parts – that’s exciting to see. And the climax of the play’s really coming together,” she said approvingly. “It gets to a level of intensity that I wanted – and expected,” she added, an edge of New York experience creeping into her voice.

Miriam Eichenbaum, now 21, wrote her winning entry, “Suicide Club,” after reading about the contest on the internet. It was the first play Ms. Eichenbaum (then 18) had ever written, and watching her closely-observed high school coming-of-age story, in a well-acted production by Valentina Fratti, you might suspect that the setting is autobiographical.

You’d only be partially right. Ms. Eichenbaum, who attended a Brooklyn yeshiva, acknowledges that she made the girls “true to the way high school girls should be. “But the situations they are in and the way they react to each other – that’s where imagination comes into play,” she explained. Though she wrote about familiar characters, seeing the actors she had helped to cast speak her lines was a revelation. “At the first reading, hearing the actors say the lines, that’s when you really get a sense of the whole thing for the first time,” Ms. Eichenbaum said. Then came rehearsals, and (typical for the festival) extensive rewrites. “Actually seeing an actor do it really helps you get a focus on what exactly is right about that character and what is contradictory, so you can resolve it,” she said.

The festival’s third produced playwright, 19-year-old Kit Steinkellner, has actually had her winning play, “Los Angeles Lullaby,” produced before – at a regional West Coast festival for teenage playwrights. Such a concept would have been unthinkable for Young Playwrights in the early 1980s, when Mr. Sondheim’s venture was seen as a radical experiment. The prolific Ms. Steinkellner, who counts Tennessee Williams and William Inge as influences, has already won a number of prizes for her plays and has directed her own work.

The difference between other venues and the Young Playwrights Festival, she says, is its glaring intensity. “We’re rehearsing six days a week and I’ve been there every day. Basically, I’m here to work.I’ve got a director assigned to me, a dramaturge, actors, a literary producer. It’s like that line from the movie ‘A League of Their Own’ – ‘there’s no crying in baseball.’ There is an understanding that in no uncertain terms,you will fix things, you will work them out, you will be professional. You’re expected to come in and deliver. I love that.”

Ms. Steinkellner, a theater major at UCLA and the daughter of two Southern California theater professionals, has been working with her assigned production team to stage “Los Angeles Lullaby,” a family drama that explores the relationships between a young unmarried mother, her estranged father, and a teenage neighbor. Ms. Steinkellner counts working with a talented female director, Ms Fratti – and alongside two other female playwrights – as one of the best parts of her New York experience.

Judging from history, odds are that one or more of this year’s winners will end up forging a career as a playwright. Famous playwrights like Kenneth Lonergan (class of ’82) and Rebecca Gilman (class of ’84) have come out of the festival, but such meteoric successes are rare.

Many of the young playwrights do find their way back to off-Broadway, however, continuing a love affair with New York theater that began at the festival. “This is the theater town,” Ms. Steinkellner said. “And creativity just explodes, because the expectations are so high that people rise to their very, very best.”

Until May 27 (Peter Jay Sharp Theater, 416 W. 42nd Street, between Ninth and Tenth Avenues, 212-279-4200).