As the time approaches for his gig on The Late Show with David Letterman, Dave Grohl is jumping up and down in his dressing room. "I always get really nervous -- every time," he says. Moments later, he and his band the Foo Fighters have finished playing, and Grohl wants to keep moving. "Let's see, what's next?" he asks no one in particular. "A fuckin' gig? Uh-huh? Let's do some more shit today!"

The Foo Fighters are about halfway through a day that only world-famous celebrities have: an early-morning visit to the Howard Stern Show; a mid-afternoon gig on Letterman; a secret show for 1,000 fans this evening; then, after that, a madcap Halloween bash at Club New York in Times Square. The band is promoting their fourth album, Letterman (RCA), but despite a busy day of doing the celebrity hustle, things are pretty calm in the Foo Fighters camp.

Before steaming ahead to their third gig of the day at Manhattan's Supper Club ballroom, the band regroups backstage at Letterman. Grohl sips a bottle of beer, and drummer Taylor Hawkins tends to a bloody finger, which he sliced on his drumkit. Hawkins is very friendly -- and shirtless throughout much of the night. Watching him suck on his finger is sort of hot, but Foo Fighters Gone Wild this isn't. A pair of blond, identical, female twins joins the band's entourage as we pile into a van outside. One girl wears a sparkling diamond ring and gives kisses. Kisses! Groupies! But she turns out to be guitarist Chris Shiflett's fianc#233;e, Kara. For a bunch of rock stars and the women who love them, it's a pretty tame bunch: Grohl's girlfriend Jordyn Blum has long, blond hair and looks like Rapunzel. She and the other ladies are classy casual -- low-slung jeans and long knit scarves. The boys wear T-shirts. There is no kooky couture fashion and no celebrity theatrics. Outside, a few dozen fans shout Grohl's name. "Step aside, people," the tour manager Gus barks at them. "This isn't a flea mart."

At the Supper Club we're ushered, Almost Famous-style, through a scummy backstage hallway and into a plush, cavernous dressing room with red-velvet everything -- pillows, curtains, banquettes. The band settles in for some "decompression time" (that's what their publicist calls it). Grohl helps his mom, Virginia, unwrap a package of hummus. Shiflett attacks a tray of wheatgrass. Bassist Nate Mendel eats an apple. Hawkins, still shirtless, plays "Bohemian Rhapsody" on a baby grand piano. Jordyn and the twins chat primly in the corner. The group is enjoying the fruits of the band's performance rider, which requires all the stuff you'd expect (fruit, water, beer) and some extras (Special K cereal, cigarettes). The bounty spills across the bar. "That's what happens when ya' top the charts," Grohl jokes, sort of.

After sound check and some dinner from Zen Palate, Grohl sits down to write the set list. "I make it different every time. You have to decide if you want to blow your load all at once," he observes. "Since this is a party show -- Halloween -- we're gonna stay away from the ballads." A few minutes later, he takes off his Levi's and slips on a pair of black Agnès b. pants (the girl downstairs wearing a Dave Grohl sandwich board would kill to steal a peek). The band is dressing up like Swedish rockers the Hives for tonight's show. Mendel gets to be the fat one with the mustache, and he seems okay with that.

Mrs. Grohl and one of her friends stand nearby, sipping wine. "David's always been the nicest boy," Mom reports. Apparently, before Grohl started touring the world with D.C.'s indie punk band Scream as a teenager, he stole the show with a walk-on role in a community theater production of Bye Bye Birdie. And he was quite the nighthawk back then. "We used to go to this hole-in-the-wall jazz club, and as he got older, he'd come with us," Mrs. G.'s friend recalls. "He'd get up on stage and play drums with the band. It was wonderful!" Someone points out that Dave has grown into a very handsome young man. "But he's got a handsome soul, a handsome spirit," she clarifies. "That's what makes him special."

A minute later, the handsome spirit bursts onstage with a blistering cover of the Hives' "Hate to Say I Told You So," prancing around like Mick Jagger. A sea of rowdy boys mosh on the ballroom floor, and giddy girls crowd-surf. Upstairs, the Foo entourage watches proudly: friends, publicists, girlfriends, producers, a stylist, a DJ, photographers, caterers, Fred Schneider from the B-52s and even Brian Marks, Mrs. Grohl's housesitter from Virginia.

After the performance, the band's dressing room is taken over by a crowd of friends, celebrities, Halloween revelers (a sexy nurse in white vinyl, Wonder Woman) and some "industry" people. Claire Danes is over there, smiling. John McEnroe (in a bright-purple, western-style shirt) chats with his wife, Patty Smyth, and politely declines photo requests. After an hour or so of good, clean fun -- there's some cigarette smoking, but no drugs; some alcohol, but nobody's drunk -- the bar has been plundered, and the party is over. A security guard trolls the room. "It's time to leave, people. The band is going home!" Grohl seems oblivious to the commotion around him as he talks to friends in the corner. Some people leave to attend the Motherfucker party at Club New York, but he balks at the thought. "I'm gettin' me some fuckin' pizza and gettin' to bed," he proclaims. He must be exhausted after making people happy all day long. His mom glows. "Have a boy, give him a guitar and let him go," she says, beaming with pride. "The payoff is great."