IT'S THE SOUND OF A THOUSAND LITTLE GIRLS SCREAMING: *NSYNC live at the Arrowhead Pond Tuesday night -- a school night. Every teen within a 30-mile radius, it seems, has broken curfew to rendezvous with Justin, JC, Joey, Lance and Chris.

Mostly, I'm here for Justin. It started as an ironic thing. Saturday evenings of humoring my best friends Sal and Sharon, a happy set of married thirtysomethings. Dinner, coffee and *NSYNC videos. Soon came the *NSYNC concert footage. The making of the concert footage. The MPEGs downloaded off the Net. The DVD with interviews and special features and frame-by-frame pause capability. I'm not exactly the demographic, but the next thing I knew, I was in the middle of the living room jumping up and down to "Bye, Bye, Bye," thinking, Gee, what would it be like to go out on a date with Justin? Would he drive? Wait, can he drive?

In the bathroom before the show, the lip gloss is in full effect. Several things to be learned: Crimped hair is back. As are glitter belts, faux backstage passes, anything rainbow, blond corn rows, lavender eye shadow and Delia's tank tops. And when claiming a member of *NSYNC as your own, be prepared for another girl to move aggressively into your territory:

Girl one, flipping through an *NSYNC calendar, points at Justin: "There's my boyfriend."

Girl two, standing in line behind her: "Whatever. That's my boyfriend." Three girls glossing at the mirror pause midstroke. A toilet flushes. Tense looks all around.

Then there are the rumors, which fly freely before the show: This is *NSYNC's last tour! JC's going solo! Justin's going solo! Lance is going to be launched into space and put into Earth orbit! Justin broke up with Britney just hours before curtain!

Since I am at this concert by myself (the madness that happens when poor impulse control collides with being turned down by every person I called an hour before the show), I've secretly adopted the 5-year-old sitting next to me. As the lights go dark, the stadium goes wild. Maybe it's the altitude at Row 408, Seat P, or maybe it's the sheer volume of girlish screaming that never subsides, but my ears really hurt. It's an awesome spectacle. The pitch-black amphitheater, the whirling glow-sticks. The pyrotechnic explosions. The 5-year-old next to me gyrates to "Girlfriend." She has all the lyrics memorized: "Won't you be my girlfriend? I'll treat you good." Mom, to the left, grabs the mini binoculars from around her daughter's neck while Dad slumps lower into his aisle seat, covers his eyes, and shakes his head. Behind us a quintet of bespectacled Asian girls belt out the lyrics to the next song, "Dirty Pop."

This must be what it was like at a Beatles concert. As if on cue, the band launches into "She loves you . . . yeah, yeah, yeah" and "Hey Jude."

A pair of girls two rows down, who are spending the entire concert on their cell phones, look at each other and shrug: This wasn't on the album.

Three quarters of the way through, three outfit changes later, the group pulls up stools to do a round of slow songs. "Basically, we're getting older now, so we can't dance as hard," Justin says. The crowd cheers even louder. They don't even have to sing because the thousand girls will sing for them. From way up here, Justin Timberlake is as big as my pinky finger. His curly blond hair is freshly shaved into a military buzz, but it's the same cherub face. "THAT'S MY BOYFRIEND," I tell the 5-year-old, pointing to the video monitor above stage. She claps and giggles. Bobbing up and down, in unison, in sync, they look so . . . cute.

Outside, post-show, two teenage boys have fashioned a poster that reads, "We got jacked for our *NSYNC tickets." A scalper sold them two fake tickets for $80 a piece. They're waiting for their ride and I'm waiting for traffic to clear out. My car is lost amid a sea of Volkswagen Beetles painted with "Honk if you love *NSYNC" or "I Luv JC." Two girls join us. Is this your first *NSYNC concert?

"It's my 13th," one answers.

"I'm not there yet," her friend says admiringly. "We're driving to Las Vegas tomorrow to see their next show."

"This would have been our first time," one of the poster guys says. He and his friend spent the entire concert outside. We shake our heads. That is so wrong. That is so sad.

"Oh my god, you should come with us!" one of the girls says. The pairs trade numbers, punching them simultaneously into four separate cell phones.

But wait, is it true about Justin and Britney?

"Vicious lie," says the taller of the two girls. "Someone saw her crying earlier today, one thing led to another . . . but Britney says they are definitely not broken up. Justin just hasn't made a statement yet."

"Boys," her friend sighs dreamily. "Argh."