GENERATION EXTREME.

Used to be the only place you could shake your groove thing was at a school dance. But dance clubs have sprung up across the country like bad Britney clones. The kind of night life that used to be reserved for adults is now idea -- give kids a place to hang out and light dance. A club with awesome tracks, a cool light show and a safe, good time that prohibits alcohol and pumps up the security (no may sound like an oasis in what's truly a bleak teen entertainment desert.

So what's wrong with this picture? In some cases, girls are getting a little more than they bargain for. You might be surprised to find some of these clubs packed with groping guys and dirty dancing that would make Jennifer Grey look like she were auditioning for The Sound of Music. Nevertheless, more and more girls, hoping to breathe a little life into their weekend nights, have wriggled into their best minis to hit the new teen club scene.

Certainly not all under-21 clubs have permissive atmosphere, but they're not exactly church socials either. Says one club owner, "I make sure there's no alcohol or drugs in our club. We provide as safe an atmosphere as possible. But when it comes to what happens on our dance floor, I am not there to keep people apart. While we don't let couples use our club as a backseat, we also don't restrict what passes for dancing these days."

Watch a little MTV, and it's not hard to see where many guys and girls get their current Inspiration. Settle in for a heavy TRL rotation of Christina Aguilera's "Come On Over Baby...." Madonna's "Music" of Sisqo's "Thong Song." You'll see more than a few examples of "freakin'," the grind-heavy, boy-on-girl groove that is considered "dancing" in a club, a lawsuit just about anywhere else. While this kind of stuff may go over well in videns, it can be much less amusing when random guys think they are up for a freakin' good time just by virtue of being on the dance floor.

We aren't coming out against these clubs, just cautioning you about what happens once you get past the velver tope.

The editors

Page through the Day Runner of your typical per-driver's license girl, and you'll see something like this. School dance. Sleepover. The movies. McDonald's. The mall. Football game. Skateland. The movies. The mall. The movies. The mall.

But seriously. It gets boring checking out the fake turds at Spencer's or getting kicked off your favorite outdoor fountain on The Avenue or--as cool as Kirsten Dunst is--seeing Bring It On for the 10th time. Which is precisely why this group of eighth- and ninth-grade girls are huddling on a sidewalk at 7:50 p.m. on a chilly fall night in Towson, Md., waiting eagerly for the doors to open at Generation Xtremes.

Marina's mom drove half of them to the under-21 dance club on this suburban shopping strip, after checking the place out on the Web. Rachel's dad drove the other half, thinking he was taking them to a school dance. "It's right here," the girls told him when they got to a nearby coffee shop. The girls unloaded there before Dad could see all the kids--older kids--hanging around outside the club.

The girls are clad in pleather and fake alligator and tiny tanks and halters and minis, glittered abundantly. Many of them got dressed and done up at the houses of friends with more lenient parents. Classmates who turned them on to the club "told us to dress like this," says Amy T., 14, who has the posture of a ballet dancer and is wearing a little black skort and gray V-neck tank that's tighter than anything she wears to school. Her brown hair is up in a high ponytail, and her brown eyes are big, round and a little wary. She's only been to one dance before, at school, and admits to some plucked nerves. "Have you heard what goes on here?" she asks.

At 8 o'clock the doors open, and the crowd heads in. Amy and her friends total six girls and one male cousin, who doesn't seem thrilled to be dragged along (and, later, barely leaves his perch, guarding purses all night). They each pay their $10 and enter the empty room--a haven for under-agers as young as 11 and as old as 20. Most of the kids seem to be between 13 and 16. Some kids are here because they aren't allowed to hang out on the steps of their apartment buildings. Some are sick of sitting at home playing Diablo. A few say they simply want a world away from adults. Tonight, they all want to dance.

The dance floor is about the size of a motel swimming pool. Video screens cover the walls. Colored lights dart around, and fog pours in. The walls are mirrored, and the floor shakes with the hip-hop techno beat. So far, the dance floor is empty, except for a couple guys from a breakdancing crew--their matching black T-shirts identify them as Avy and Neo--who are head-spinning and popping and locking on a rubber circle in the back corner.

The dashing lasers illuminate the sparkles on the girls' shoulders as they try unsuccessfully to goad each other onto the barren floor.

"C'mon!"

"C'mon, dance!"

"You!"

"No, you!"

Generation Xtremes has quickly become popular, as have the many dance clubs throughout the country--once the domain of adults only. The clubs--with names like. The Realm and Odyssey and Medusa's--have popped up not only in suburban enclaves like Towson, but also in big cities like Boston and Chicago, ski resorts in Colorado and Vermont, beach towns in Florida and California, and a whole list of middle-of-nowhere towns like Valparaiso, Ind., and Susquehanna Township, Pa. Some cater to teens one night a week, others all the time. Some proprietors say under-21 clubs are less trouble and nearly as much profit as the adult bars they once ran.

This club, which stays open 'til 1 a.m., is advertised on the local Top-40 station. But, mostly, it's become popular by word of mouth. That's how Amy and her friends found out about it. Their classmates, club regulars, arrive around 8:30, wearing even tighter and more revealing outfits. They are also a little less intimidated by the deserted dance floor. Four of the girls head out and intertwine their legs with each other, shaking their hips and butts to the music like a smooth-geared machine of leather and Lycra and skin. Amy watches with her hand over her mouth and giggles.

She finally heads out to the dance floor with her pals: Angie B., 13, in her yellow tank and black mini; Lisa B., 14, in faux alligator pants, platforms and black tee that says "Angel" in red glitter; Jane R., 13, in a grey-flowered stretch top and tight black pleather pants; Marina M., 13, in hoop earrings, shorts and a pale blue tank with bra straps showing; and Rachel M., 13, in a black velvet jacket with a fur-lined hood, which she's reluctant to take off because the lizard halter she's wearing underneath is all about her bare back. Rachel has a navel ring--she's bold that way- but, still, it takes her a good hour to take her jacket off Then, she puts it back on twice before taking it off for good.

Out on the dance floor, they move to the music, spun by DJ Impulse, which is too loud to talk through--although, yelling into one's ear works OK. A group of guys at the soda counter stands there and watches. And Marina stands there and watches. "Just do what everybody else is doing," Amy yells through the noise. "It's not that hard!"

But it's hard for Marina, who's clearly weirded out by this place. She chews her hangnails and preoccupies herself with finding a place for her purse. She brings it to a tall table, where Rachel's cousin Luis sits stone-faced with a bag of microwaved popcorn. She decides to hide it near a speaker. She puts it back across her shoulder. She brings it to the table again. And so on. Anything so she doesn't have to dance. Or, so she doesn't have to dance like that. Rachel, Jane, Angie and Amy are gyrating on the speakers. "These are my friends," Marina says with a wary shrug.

This isn't your mother's teenage hangout. This isn't even your big sister's teenage hangout. The place may as well have a huge black-and-white sticker slapped on the door that says, "Parental Advisory: Explicit Everything."

Well, not everything. Not the counter where a Heather Graham look-alike in platforms sells soft drinks-Pepsi, Jolt, Red Devil, Fruit Works, non-alcoholic daiquiris and pina coladas-and popcorn. Not the display case where you can buy fake nose rings and baby tees and mini glowsticks to roll around on your tongue. Not the unmanned snack bar with signs for mozzarella sticks and buffalo wings, abandoned since nobody ever bought food. Not the back room, which has pool tables and World Cup Soccer pinball and air hockey and a free-throw machine and neon bar signs advertising Snapple, K2 and Mountain Dew.

But on the dance floor is a world that would come as a surprise--really, a shock-to many parents. Girls climb atop speakers to dance in a line facing the mirrors, their shorts so short their butts hang out. The boys, draped in baggy denim and plaid, stand beneath them and stare. The music is Hot Boys, Cash Money, Akinyele--lyrics with F-words and MF-words and talk about sex.

The moves? Think MTV's The Grind, cranked up several levels.

"Come here," a guy tells Jane. "I know someone who wants to dance with you."

"Who?" she asks.

"The guy in the white shirt."

Jane checks him out and delivers the blow-off, politely: "Maybe later."

Jane and Rachel dance the night away, pretty much left alone by boys. But, often, there's no asking involved. While girls dance, boys come up from behind, grab their hips and hold the girls against them as they bounce to the beat. They stay as long as the girl seems into It--the looks on the boys' faces alternate between utter seriousness and "I can't believe I'm so lucky" grins--and then they move on to find someone else.

This happens to Angie first, after about an hour of dancing, her blond ponytail finally let loose. She doesn't mind as the boy grinds against her.

Then boys come up to Lisa and Amy and "freak." They don't greet the girls with a "hello," don't even look them in the face. Amy goes along with it, unsmiling, but eventually mentions a fictional boyfriend to get the guy to leave. Later, she says there's nothing flattering about the attention. "It's not like a boy likes you when he comes up to you," she says. "He just wants to dance with somebody." The guys from her school who have come tonight don't dance-- they just sit with an expanding collection of empty plastic daiquiri cups.

The gang doesn't see the guy who's parading around waving a pair of yellow-flowered panties above his head. They don't see the security guard playfully slapping a girl on her pleathered butt. But they do see some other things: A boy dancing with a girl who has glasses and a Felicity 'do rubs his hands all around her red halter and black mini. Another boy--a 15-year-old regular named Craig--has a girl bent over at the waist, and he pushes up her already-short skirt as he dances with her. She eventually staggers away, laughing, and falls on the ground.

Parents who let their kids go to Generation Xtremes are comforted by the hulking security guards at the door, who look like they're one audition away from the WWF. Boys are frisked; fights are few. No cigarettes are allowed, and alcohol and drugs are banned--but some kids arrive already impaired.

Mostly, the teens are sober. However, many are--for hanging in a place where virtually no kisses are exchanged--way too sexual. Amy continues to dance with her friends, and an occasional passerby dances with, essentially, her back. Even though it makes her uncomfortable, she goes along with it. "What are you going to do?" she asks.

The girls are getting picked up at midnight. At a quarter 'til, they sit on stools, their glitter sweated off, and contemplate the evening while the music continues to pound. Jane says the only thing that made her uncomfortable were her pleather pants, so tight on the dance floor that "I couldn't shake it." She and Rachel plan on coming back next week.

Amy has found the club "a little overwhelming." While she thinks the boys are pretty cute, she's not sure she'll come back. Marina, who has spent most of the night leaning against the mirrored wall and walking back and forth to the bathroom with her equally uneasy friend Laurie, says she definitely has no use for this place in the future.

Then the girls take off, ears ringing and bare shoulders chilled by the cold midnight air, to the place blocks away where their ride is waiting.