LAS VEGAS--There are two sides to Vegas this weekend--the sun-baked, heat-stroked daytime and the glitzy, club-fueled nighttime.

Both involve loads of scantily clad women and the men who fancy them, and the MTV Video Music Awards had both sides covered Saturday, as the mtvU Rookie Showcase featured Boys Like Girls and Peter, Bjorn & John during the day and DJ Questlove, Robin Thicke, and Maroon 5 rocked the VMA Fandemonium benefit for LIFEbeat at night.

With hundreds of attendees packed in and around the Palms Resort Casino's immense pool in the afternoon, the mtvU Rookie Showcase looked a lot like one of MTV's famed spring break parties. It featured two up-and-coming bands that have already achieved some success but not the worldwide fame of many of the artists in town for the VMAs this weekend.

Boys Like Girls

Martin Johnson of Boys Like Girls/Photo: Jim Welte

Boys Like Girls, the Boston-based quartet that has ridden the success of the hit "The Great Escape" to alternative rock buzz status, kicked off the day with a set of emo pop rock primarily about--shockingly--boys liking girls.

Frontman Martin Johnson played the part, working the crowd in black skinny jeans and a ratty Ramones T-shirt. "You can't beat this s*** can you, rocking out by the pool at the Palms," he said.

But in addition to odes to the obvious, the band mixed in still poppy but more nuanced material as well, like "Dance Hall Drug," a cautionary tale about the teenage urge to party too hard, too young.

It was solid but unremarkable set, more noteworthy as a proper soundtrack for some scintillating people-watching.

Peter Bjorn & John

Peter Moren of Peter, Bjorn & John at the mtvU Rookie Showcase/Photo: Jim Welte

The Swedish trio of Peter, Bjorn & John have one of the year's catchiest tunes in the whistle-happy "Young Folks," a song that has managed to make its way well outside of the indie rock circles in which the rest of the band's material traffics.

The band kicked off the set with "Let's Call It Off," a dose of retro '60s pop that fit in perfectly with the sunny poolside scene. The wry "Amsterdam" followed, with Peter Moren ceding lead vocal duties to the the more low-pitched crooning of bassist and producer Bjorn Yttling.

The band's live sets have something of a crafty bait-and-switch to them in that they draw fans in with the catchy retro pop but mix in plenty of distortion-heavy rock, and did just that on Saturday. On "Young Folks," Moren jumped off the stage and climbed back up on a small piece of scaffolding, which teetered back and forth as he ascended, reminiscent of his offstage escapades at Lollapalooza last month.

But the song also incited the fantastically strange sight of bikini-clad girls whistling along fervently to a Swedish pop trio. The trio's sound is a superb mix of catchy pop and an off-kilter, lo-fi sound whose growing popularity is a good thing for rock music.

VMA Fandemonium benefit for LIFEbeat

Maroon 5, Robin Thicke, and Hayden Panettiere/Photo: Jim Welte

The party moved over to Mandalay Bay in the evening, with DJ Questlove, Robin Thicke, and Maroon 5 all set to rock the House of Blues for a Neutrogena-sponsored show benefiting LIFEbeat, the music industry's nonprofit group dedicated to AIDS awareness and prevention in the US.

Questlove, the drummer and cofounder of the Grammy-winning, Philadelphia-based hip-hop band The Roots, was first up, blazing through a set of hip-hop, soul, disco, and rock on the turntables. Questlove has a famously immense record collection, and seemed to draw on mostly all of it, getting the crowd warmed up with a mix of classics and new favorites.

Robin Thicke

Robin Thicke/Photo: Jim Welte

In the past two years, this sly crooner has morphed from emerging artist and acclaimed songwriter for others--as well as the son of Growing Pains star Alan Thicke--into a hugely popular artist in his own right.

Parked behind a keyboard and accompanied by a tight, three-piece funk band, Thicke kicked off the set with "2 the Sky," a gospel-influenced burner from his latest album, 2006's platinum-selling The Evolution of Robin Thicke.

As Thicke pounded on the keys and bounded about the stage throughout the set, comparisons with Justin Timberlake were hard to avoid. Both draw on classic R&B for their blue-eyed soul, flexing their adept vocal muscle on a wide range of material.

The disappointment of the night came during Thicke's standout track "Shooter," the "Mass Appeal"-sampling, Lil Wayne collaboration that appears on both men's latest albums. It's a fantastic track, and Thicke's keyboardist filled in admirably on the guest rap slot in Wayne's absence. But with Wayne billed as one of the night's attendees and his appearance on the red carpet later in the night, it would have been cool to see them perform it together.

Maroon 5

Maroon 5 at the House of Blues/Photo: Jim Welte

Whereas Thicke brings a gospel influence to his strain of blue-eyed soul, the Adam Levine-fronted Maroon 5 do so with a rock-fueled sound. Kicking off with "If I Never See Your Face Again," Levine sang an ode to an old flame.

The band is quite an odd sight, with the chisel-chinned and tattooed Levin crooning soul tunes while guitarist James Valentine and bassist Mickey Madden pound away, looking more like dead ringers for a Freedom Rock band than a massively popular LA soul-rock band.

"The Sun" gave Valentine some room to show off his guitar chops, as he and Levin pushed the track into an extended jam. But the set was mostly chock-full of exceedingly accessible sing-along rock that owed more to the likes of classic soul than classic rock.