On October 9, the first night of the Yeah Yeah Yeahs' Australian tour, flamboyant singer Karen O was doing what she normally does during a show: spinning, twirling, yowling, squealing. Your usual punk-rock sex kitten stuff. Until she did an unintentional header off the stage, that is, taking a monitor (which landed on top of her) with her.

"It was a very terrifying thing to witness," recalls guitarist Nick Zinner. "I wouldn't be surprised if she's a little more tame [in future shows], physically. That might be a good thing, because she's been tempting fate. For the past six months, we've been trying to outdo ourselves, but we've reached a point where you can't really achieve next-level status without being able to fly."

Miss O performed one more song that night, lying on the stage with an ice pack on her head, and then was taken to a Sydney hospital, effectively giving the band a much-needed night off in a year that's been demanding, to say the least.

Zinner and O formed the Yeah Yeah Yeahs back in 2000, with drummer Brian Chase joining up later on. The songwriting was fast and furious, and soon the band landed high-profile supporting slots on tours with the White Stripes and the Strokes. A showcase at the 2002 South By Southwest conference secured the group's exciting, fleeting status as the next big thing.

After that fateful performance at SXSW (a shindig Zinner deems "our seventh circle of hell"), the big labels were clamoring for signatures, offering deals left and right. The Yeah Yeah Yeahs, still fresh and young, found themselves faced with a difficult decision. The nascent band already had a relationship with indie label Touch and Go, which had released the group's first two EPs, Yeah Yeah Yeahs and Machine. Walking away from the people who had helped them proved to be almost as hard and painful as passing a kidney stone.

"It took forever, basically due to indecision," says Zinner. "We were really fortunate in that there were a lot of people who were hungry [to sign us]. It ultimately came down to a choice of whether we wanted to go with an indie or a major. The record was finished before we actually signed to anyone, but the process just took forever. But it became clear after one night's discussion, and it was a risky move, leaving Touch and Go, who we've become really close with, and saying, 'Let's try this with a what-if perspective, sort of take our chances with it.' "

Diving headfirst into the big leagues, the group signed with Interscope, an imprint of Geffen, and finally released Fever to Tell, their debut full-length, in April of this year. You could almost hear a collective intake of expectant breath from those whose thirsts for arty punk rock were not slaked by the band's meager prior output. And they were not disappointed. Once the buzz-saw guitars fill up the room, teetering on the fine line that separates really sloppy and incredibly precise, you find yourself enveloped in a huge, sexy sound, underscored by Chase's technically proficient, driving and intelligent drumming. Up front is O, Siouxsie Sioux's bastard daughter, uttering guttural alley-cat growls on "Rich," then screeching breathlessly like a little girl on "Tick," her lungs not large enough to push out all the air and energy she's got to expel.

Zinner is cagey when asked how he makes his one guitar sound like ten. "I wish I could tell you that I've got a five-fingered tail. I am looking to sign a deal with the devil, though. I'm available." The tiny little guy with spiky hair laughs. "It's just like a desire for fullness, I guess. Just try to maximize everything, and having a good time is helping, too."

The last third of Fever to Tell enacts a dramatic shift in mood. On "Maps," gone is Karen O's Joan Jett sneer and sexual posturing; in its place is a wounded young woman whose heart you can hear breaking when she sings, "They don't love you like I love you." It's startling, really, to be thrashed about musically, left reeling and panting, grinning dementedly, then dropped abruptly into the pages of a lovelorn girl's diary.

"That record is songs that we had been writing and touring on for, like, the past year and a half," explains Zinner, "so it's sort of like a record of our eternal imbalances during that period.

"When Karen and I first started doing music together, we were doing really, really dark shit, and the Yeah Yeah Yeahs was sort of a counterbalance to that, a separate entity. There's only so long that you can hold those separate pieces at bay, and I guess we had more sentimental things on our minds. That's where a lot of the songs at the end of the record came from."

Part of the motivation to include these quieter, sadder songs on the record was strategic. "The last thing we want to be is a one-dimensional party band. We definitely have those instincts, but there's just so many other contradictory instincts brewing about that eventually find their place," Zinner says. But all one has to do is listen to "Art Star"(from Yeah Yeah Yeahs), "Machine" (from the EP of the same name) and "Modern Romance" from Fever to Tell back to back to know that this trio is no one-trick pony. The only problem is that they have little time these days to flesh out those divergent instincts.

"We've only had time to write four or five songs in the last eight months. Before we started touring, when we were playing one show every three weeks, we'd always have new songs for every show. We're sort of like used to having a really high rate of output and creativity. We don't really know how to write on the road, and the breaks that we have at home we just want to rest."

This obstacle, plus other projects the band members have going -- including Zinner's new book of photographs, called Slept In Beds (found at eviltwinpublications.com) -- means that the Yeah Yeah Yeahs' public will have to satisfy itself with this current tour, because time off and recuperation is the order of the day come the end of the year.

That is, if everyone can make it through this tour without consummating their flirtation with the grim reaper.