''This could be really embarrassing,'' Mila Kunis cautions, taking her seat behind a plastic Rock Band drum kit. ''I'm in heels!'' The actress is hanging out backstage at the July 12 taping of VH1 Rock Honors: The Who, joining Pearl Jam, Foo Fighters, and others to celebrate the legacy of that seminal band, which has 13 songs available on the videogame she's about to play. She dials up the Yeah Yeah Yeahs' ''Maps,'' and hits the kick-drum pedal with stiletto precision. A minute later, it's obvious that she's being extremely modest: Kunis is one serious Rock-er. ''Don't be that impressed,'' she says mid-solo, but even Dave Grohl, who's hanging nearby, starts paying attention. ''Okay, be a little impressed. I can get 99 percent if I take my heels off.''
Welcome to the future of music, where the living room now increasingly cluttered with plastic guitars, drum sets, and microphones is the new garage. So-called ''rhythm'' games have blown up over the past year, with Guitar Hero III: Legends of Rock selling 11.3 million copies and Rock Band moving an additional 3.5 million. Together that adds up to more than $1.7 billion in revenue. But it's not just sales: The excitement over these games is sparking renewed interest in music itself, allowing players to experience songs in a new way and turning kids on to a universe of tunes. In the coming years, these games could launch bands, resurrect faded careers, and just maybe reshape the music industry. ''People have moved to this 'wallpaper' relationship with music, where they listen to it while doing other things,'' says Alex Rigopulos, CEO of Harmonix, the company behind Rock Band. ''We're making them active participants, and they've demonstrated a willingness to pay for that experience.''
We'll find out how much this fall, when Rock Band and Guitar Hero release eagerly awaited new editions, each retailing for close to $200. Rock Band 2, which hits stores Sept. 14, is rolling out new instruments and a song library that tops 500 tracks. Guitar Hero: World Tour, due in October, will now add drums and a microphone. Rock Band is hawking full albums (on tap: Foo Fighters' Colour and the Shape, Red Hot Chili Peppers' Blood Sugar Sex Magik, Jane's Addiction's Nothing's Shocking, and a No Doubt best-of), while Guitar Hero is ditching all cover versions in favor of the original recordings. Rock Band 2 features a drum training mode, and World Tour offers a studio function that lets players create their own music and post it online. With both brands spending large sums on advertising, expect the phenomenon to absolutely explode.
Part of the reason these games have hit such a chord even when overall music sales have been declining is that they bridge the generational and gender divide. Rhythm games are the Xbox equivalent of American Idol, and families are getting addicted together, with parents and kids alike strumming along to songs like Black Sabbath's ''Paranoid.'' ''From age 5 to 55, man or woman, Guitar Hero is for everybody,'' says Kai Huang, cofounder of RedOctane, which developed the game (Activision now owns the Guitar Hero franchise, while MTV Games acquired Harmonix in 2006). ''It's like Twister from hell,'' says Mötley Crüe bassist Nikki Sixx of the family jam sessions in his house. As a result, young people are now getting exposed to and falling in love with a broad swath of rock history. ''There's nothing quite like being told by your 10-year-old son that you're not singing Nirvana's 'In Bloom' right,'' laughs matchbox twenty frontman Rob Thomas, an early fan of both games. ''I couldn't be prouder.''
NEXT PAGE: Compared with iTunes, ''the artist's split is bigger [in the rhythm games]. And if you own the masters and the publishing, it's humongous.''