Los Angeles is a hip-hop town, and on Thursday night (3/25), the city's Wiltern Theater played host to two of the genre's rapidly ascending bands, hometown favorites Black Eyed Peas [ tickets ] and uber-hotshots N.E.R.D. [ tickets ]

Both bands love to party, throwing down shark-sized hooks and beats, and always demanding the audience play its part in the festivities. The two-hour gig opened with Black Eyed Peas' cartoonish MCs breakin' and poppin' across the stage and ended as N.E.R.D. blew up on a stage brimming with rappers, musicians, girls in mini-skirts and Justin Timberlake.

Taking a cue from Motown's classic hitmakers, both of these headliners have backing bands--and good ones too. Black Eyed Peas are equipped with a funk-inspired four-piece whose sound is greater than the sum of its parts. Up front, of course, BEP's MCs rally the crowd with maximum energy and style, hands always high in the sky, heads always bobbing.

The L.A. group lit the fuse with "Hands Up," the song's immediate refrain sparking an inferno of movement in the crowd. As part of '90s dance crew Tribal Nation, Will.I.Am and Apl de Ap learned early of the power of physical movement at a rap show. No surprise, then, that dancing is as integral to BEP's performance as any musical hook.

Will, decked out in a big safari hat and black velvet smoking jacket, and Apl, wearing oversized Bugs Bunny gloves, pop-rocked across the stage--offering delicious eye-candy. Likewise, newest member Stacy Ferguson showed off her tight six-pack, undulating her midriff throughout the night, while bellowing impressive blasts into her mic.

The group rolled through an hour-long set that included "Labor Day (It's a Holiday)," their '98 hit "Joints and Jams," and "Let's Get Retarded." But the highlight had to be the finale, with an animated jam that included jaw-dropping solos from everyone onstage. Drummer Keith Harris was super-hot, pounding mad rolls across his kit. When a roadie appeared behind Harris holding a snare, the drummer started pounding the drum--even following the roadie to the front of the stage without missing a beat. Then he took a page from Jimi Hendrix, laying on his back to smack the drum some more.

And when Justin Timberlake--doing his best B-boy impression--hit the stage to join BEP for "Where is the Love?" the crowd went berserk. Is he for real? Timberlake impressed as he beat-boxed into his microphone with Will.I.Am, proving he can flow like anyone from Brooklyn to Long Beach.

N.E.R.D., backed by Spymob, was a suitable follow-up, though one had to wonder whether BEP should have gotten top billing for this hometown show. After all, it seemed many in the crowd headed for the exits a few songs into N.E.R.D.'s set. Those that stayed were treated to a lively collection of tunes that spanned heavy metal, R&B, hip-hop, and rock and roll.

Led by the charismatic Pharrell Williams, N.E.R.D. plowed through an 80-minute set that was dark, loud, and sometimes uneven. But it was also damn lively.

"Brain," off the band's debut "In Search Of ...," was a sexy romp of '20s-inspired jazz percussion and modern day hip-hop style. By the time Justin Timberlake returned to croon soulful lines on "Provider," N.E.R.D. was in high gear. Pharrell pulled a hottie up from the crowd to shake it on the hit "She Wants to Move." (The woman went on to molest nearly everyone on the stage.) "Backseat Love" was all dirty funk, nasty enough to awaken the ire of the entire Republican Party. With "Bobby James," N.E.R.D. has written a cinematic ballad, with epic minor chords, and colorful, dramatic vocals.

The band left the stage to wild applause. Just then, Timberlake returned to exhort the fans: "Will y'all please let N.E.R.D. know that you ain't goin' home yet!"

Pharrell, Shay and Chad Hugo roared back with "Rock Star," its grinding guitars recalling the band's predecessors Fishbone and Living Colour. As the last measures faded, Pharrell shouted, "Are you ready for pandemonium?" Applause ringing out, he promptly peeled off his shirt, eliciting a robust squeal from the ladies down low.

As they closed with the pounding "Jump," the band filled the stage with members of Black Eyed Peas and the girls from the audience all vying for space up front with Timberlake. It was a tried and true effect, proving that while hip-hop may evolve, it never strays too far from its origins.