This fall, for the third consecutive year, an unusual crowd will sweep through the front doors of New York City Center, home to some of the world’s most high-profile dance companies. Brooklyn 20-somethings will file in alongside august patrons of the ballet. Curious first-timers will take their seats beside ardent, lifelong fans of Paul Taylor and American Ballet Theater.

Once again, it’s time to “Fall for Dance.” At the third annual festival, every seat in the house will again be priced at $10, which means that even the most financially strapped dance lovers — and dancers themselves — can afford to attend.

It was this vision that inspired City Center President and CEO Arlene Shuler to creat the festival in the summer of 2003. “Part of what we wanted to do with ‘Fall for Dance’ was to attract a younger and more diverse audience,” Ms. Shuler said recently. “Many audiences are older, and we believe that in order to keep dance a viable art form, we need younger audiences to keep regenerating the audience that we have.”

Ms. Shuler’s inspiration was the beloved Delacorte Dance Festival of the 1960s and ’70s, a free (and free-spirited) event held in the open-air Delacorte Theater in Central Park. With its eclectic, mix-and-match bills featuring wildly disparate companies, the Delacorte Festival made a lasting impression on an entire generation of dancegoers. “You could come and see a lot of different work, and you were exposed to artists you might otherwise not have seen,” Ms. Shuler said.

Delacorte Dance Festival audiences tended to be enthusiastic, game for anything — and unusually diverse, so Ms. Shuler thought a $10 (“the price of a movie”) City Center version might attract a similar crowd: younger, less familiar with concert dance, inquisitive.

Ms. Shuler’s idea for a populist dance festival inspired funders as well. Within six months, she had raised $1 million — enough to launch the first “Fall for Dance” festival in October 2004.In that year and in every year that has followed, approximately 85% of the festival’s cost was subsidized by donations, allowing City Center to sell the tickets for $10 apiece. (By contrast, an orchestra ticket at City Center normally costs around $80.)

The inaugural festival’s six performances sold out in the first seven days, with lines forming outside the City Center box office. After last year’s festival sold out in three days, Ms. Shuler decided to add four additional performances for this season. On Sunday, when tickets go on sale for this year’s installment, an extra 11,000 tickets for the festival’s 10 performances will be available for purchase.

“If you walked up and down the line,” the festival’s artistic adviser, Elise Bernhardt, recalled of previous year’s ticket lines, “it was really young people waiting to buy tickets — students, dancers, all the people you wanted to see there.”

Indeed, data collected by City Center in the first two seasons suggest that on some nights, as many as a third of the audience members were younger than 30.

Choreographer Elizabeth Streb, whose company will make its second festival appearance this year, was struck by the energy in the house. “It was an extremely young, extremely mixed audience — not necessarily a dance audience. I didn’t recognize the demographic there at all,” Ms. Streb said recently. “Most dance audiences watch dance in a particular way. They are not as demonstrative as this audience was.” In contrast to the stereotypical subdued audience, “Fall for Dance” crowds have been lively and vocal. Performances in past years have been punctuated by gasps, shouts, giggles — and often, thunderous ovations.

“The audience is completely charged,” said a former New York City Ballet dancer, Peter Boal, who performed a solo at the inaugural festival and will bring Pacific Northwest Ballet, the company he now directs, to this year’s festival. “And the acts build on each other. The evening starts at a high point and goes higher.”

“They organized it in such a way that the entire audience was so jazzed up,” Ms. Streb recalled. “It’s almost like when you walked out, all the work was done for you.”

Ms. Bernhardt, along with Ms. Shuler and others, crafts the eclectic lineups carefully. “We look for pieces that are going to be engaging both to an already-serious dance audience, and to an audience that is brand-new to dance,” Ms. Bernhardt said. “Then you have to figure out the right sequence, the one that will really work. It’s chemistry. It’s a little like cooking — not too much garlic, not too much spice.”

Big-name companies (ABT, NYCB, Alvin Ailey American Dance Theater) often “anchor” programs, but each bill also features edgier, more experimental fare. Last year, for instance, a dancer from Les Grands Ballets Canadiens de Montréal began a wild solo onstage while the crowd was still filing into the fully lighted theater — a development that bemused both newcomers and dance die–hards.

Eschewing time-honored dance hierarchies, the bills position circus-like acts alongside classic ballet excerpts; tap, flamenco, and folk dance are programmed with postmodern and modern work. Seminal works in the history of dance — like Charles Moulton’s “Precision Ball Passing” or Mr. Boal’s revival of the solo from “Episodes,” created by George Balanchine on Paul Taylor — are on the same program with newly minted dances. According to Ms. Shuler, all companies — from the famous to the obscure — are paid according to the “same set formula.”

“‘Fall for Dance’ took people from all different places in the dance world and put them on the same stage,” Mr. Boal said. “And I thought that equalizing of the dance world was a beautiful gesture, inspiring to everyone involved.”

In addition to introducing new dance audiences to a wide range of material, Ms. Shuler’s dance-exposure campaign has worked in another, perhaps unanticipated direction: It has also exposed longtime fans of Ailey or Taylor to the work of emerging companies.

Take, for example, the case of Ms. Streb’s troupe. The group appeared at the first “Fall for Dance” festival, where volunteers distributed brochures advertising the company’s upcoming shows in Williamsburg. “We did surveys at our home shows that fall, asking where people had heard about us,” Ms. Streb recalled. “And many of them said, ‘Fall for Dance.’ And they were willing to come out to Williamsburg and take a chance on a whole show on the basis of seeing just a little bit of us.”

This past summer, Ms. Streb’s company had a coveted slot at the Lincoln Center Festival for the first time. “I absolutely think being on a stage at City Center made a big difference in our getting invited,” she said.

Similar effects may make their way across the dance world. According to data kept by the invited companies, much of the audience at “Fall for Dance” will go on to attend dance performances at other venues. “I think there’s been a huge impact in other spaces across the city,” said Ms. Bernhardt. “It’s definitely been beneficial for the entire ecosystem.”

Whatever its trickle-down effects, the festival has created a rare commodity in New York dance: audience that’s game for anything. “If you pay $100, there’s an expectation — that you have the right to get a certain amount of something that you like,” Mr. Boal said. “If you pay $10, it’s more, ‘Let’s see what we get.’ There’s enthusiasm in the audience, and they’re open to risk.That’s a great audience that has that mind–set.”