By the time the third band was playing, the crowd had grown smaller, but rowdier.

A bushy-haired singer stepped up to the microphone.

"This next song is called `Tomorrow We're Done'," he said, fingering a guitar string. "It's about how making mistakes is all right, because, well, tomorrow we're done."

With that, the members of "Merging Fate" unleashed a thunder of rock music, turning two dozen teenagers into a sea of twisting torsos, flailing arms and banging heads. An air hockey player, 20 yards away, plugged two fingers into his stage-facing ear -- and went on swatting the puck with his other hand.

As the song progressed, a guitar riff surfed up and down through the din. And then the song slowed, and a backpack-toting fan shuffled onto the stage, a can of Diet Coke in hand.

"Pump it up!" he brayed, ushering in the next number.

Welcome to Friday night at the Beanery, this town's teenage rock house. Run by the town's Parks and Recreation Department, the music hall hosts one or two shows a month, September through May.

Next fall, the Beanery will kick off its 25th year of concerts. Though fashions, décor and music scenes have changed, the low-ceilinged building on Old Dam Road has retained the same mission since its inception: a place for youths to meet up, play games, watch or perform live music, and, on at least one occasion -- as in John Mayer -- springboard into fame.

If you walk through the front doors of the place and turn left, you stand about 30 yards from the stage. To get there, you pass a candy-stocked concession stand; a big-screen TV; tables for ping pong, pool and air hockey; and rows of plush couches for lounging. Then a hardwood floor leads up to the stage -- a foot-high platform ringed by dangling Christmas lights, with two boxy speakers perched up front.

Those two speakers have been used without replacement at the Beanery for over 20 years. But the Fairfield Elks Lodge recently donated about $2,000 to the Parks and Recreation Department to buy some replacements. This summer, Ginna Paules, the department's youth coordinator and Beanery director, will go shopping.

According to Patty Klein, Paules' predecessor at the Beanery, the venue opened in 1986, during the first year of the Town Youth Council. It was designed as a high-school night club, aimed at highlighting high-school bands, and was decorated by the founding teenagers. At the time, child abuse was making headlines and CBS had run a special about a girl named "Beans," who had been abused. The teenagers -- whom Klein described as "a very aware group of kids" -- named their new music hall "The Beanery," in the girl's honor.

Since then, the Beanery's shows and décor have reflected the changing whims of a quarter-century's worth of teenagers. When Paules took over in 1996, for example, the walls were painted black, creating a temple-like feel that suited the thumping heavy-metal music that then was in vogue.

Now, those walls are splashed with colorful murals and sprightly designs. On one wall, at stage-left, amid a rainbow of teenage hand-prints, there's a painted lyric from a Dave Matthews Band song -- "Eat, drink, and be merry, for tomorrow we die," it says.

Attendance has oscillated over the years, but has been running high this season, thanks largely to websites like Facebook, which help bands promote themselves, Paules said. Heading into Friday night, for example, the Beanery's Facebook page had around 70 confirmed guests, while each of the four bands that were to play had sent out their own invitations.

More than 70 guests turned up. Each paid a $3 cover charge, which goes to the Jacky Durrell Scholarship Program, which gives four $1,000 grants to high school seniors every year. And while Friday was probably the second-to-last show of this season, it offered -- in the night's first set -- a glimpse of talent that's on its way.

The first set consisted of a rotating cast of some 20 middle and high school students who take lessons at The School of Rock, a music academy on the Post Road, which opened in July 2008. The show began around 7:15 p.m. Frank Perrouna, the school's director, bounded around the place between songs, directing students to guitars, keyboards, drums and microphones like a basketball coach running a complex offense.

The first half-hour featured songs by Aerosmith and Boston. Then four middle-schoolers and an Osborne Hill 5th grader took stage and churned out Styx's "Come Sail Away."

Parents filed onto the dance floor. They clapped their hands in rhythm as the tempo picked up. Then, after the song's first chorus, the music paused.

Ethan Furman, 9, slapped drumsticks together and the three guitarists leapt into the air. Tim Dutter, an 8th-grader at Tomlinson, landed mid-chord, skipped to the microphone and crooned:

"I thought that they were aaaangels, but to my surpriiiiiiiise,

We climbed aboard their staaaaaarship, we headed for the skiiiiiiiiies."

(The crowd joined in.)

"Come sail away, come sail away, come saaaail away with me! Come sail away, come sail away, come saaaaail away with me!"

By the song's end, the other guitarists were screaming their backup vocals and Dutter's arm was doing a reverse wind-mill, slamming guitar chords. His mother looked on, wide-eyed.

"I've never heard him sing this song before," Amy Dutter said excitedly. "But I'm floored." Three weeks earlier, she said, he played the song at a New Canaan venue for the first time. When he came home, she asked him how the show went. "And he said, `It was great, mom. Nobody came but it was amazing.'"

Many were there this time around. After the set, Dutter chatted with friends who came to see him. Someone asked about his windmill guitar technique. "I didn't know what I was doing, but I was loving it," he said.

While he spoke, the next band, Disabled Time, made up of juniors and seniors from Fairfield Ludlowe High School, were setting up for their set. Seventeen and 18-year-olds were filling the dance floor, piling about six rows deep

Perrouna, meanwhile, was at the front door, explaining to a guest the School of Rock's mentality.

"The formula's simple," he said. "You give a kid 20 years' worth of classic rock and say: `This stuff works. It still plays on the radio every day, in every city around the world. Now let's learn it...'"

As Perrouna spoke, out walked the budding, wind-mill-jamming rock star. A guitar case in one hand, he sipped on Monster Energy drink from the other. Were this a decade from now, he could have been swarmed by doting fans asking for autographs.

Instead, his mom spoke.

"Did Tim help you clean up afterwards?" she asked Perrouna.