Although the term “East meets West” is usually used to describe cross-continental cultural exchange, it can also be applied to Los Angeles’ music scene. With an exploding underground art movement centered around Eastside areas, such as Silver Lake and Echo Park, many local bands have avoided playing the traditionally more mainstream Sunset Strip in the West.

Eastside · Sarah Negahdari of The Happy Hollows performed at The Viper Room last Friday night. - Photo courtesy of Lydia Chain

But as displayed throughout the Viper Room’s “10 Days of 2010” concert series, some of the city’s most popular Eastside acts can hold their own against the fabled Strip’s rocking reputation.

Last Friday’s show, for example, — which, keeping with the number theme, cost only $10 — was like Los Angeles’ underground-music peacock fanning its pop-rock plumage. The KROQ promotional van was parked outside, and the cocktail waitresses were top-heavy and under-dressed, but the Happy Hollows, Gangi, Useless Keys and the Soft Hands took over the infamous venue like it was a free Monday night show at Spaceland.

With all of the aesthetic requirements for an Eastside band fulfilled (dreamy singer, petite and brooding female bass player, etc.), Useless Keys opened the show with its catchy, Led Zepplin-y jam sessions. Although generic-sounding guitar wailing crept in a few times and several songs evoked drug-related cartoon nightmares, Useless Keys was, in the end, more impressive than unnerving.

Using the night as an excuse to emerge from recording hibernation, the L.A.-via-New York experimental-folk duo Gangi made the most of its short set to showcase a cross section of its sonic abilities. Fronted by sometime-DJ and perpetual sample-maker Matt Gangi and supported by newly added bass player Oliver Hild, the band utilized every keyboard, guitar and synthesizer on stage — of which there were many — to create their masterpieces.

In addition to stripping down to traditional instrumentation for its newly written tunes, Gangi used synthesized keyboard notes, pre-programmed beats and looped sounds from a pedal board-type array to add texture to older, rawer songs.

Matt Gangi of Gangi also performed at The Viper Room last Friday night. - Photos courtesy of Lydia Chain

Throughout the frontline changes, however, new drummer Eric Chramosta’s impressively technical skin-hitting remained constant. Never content with a 4/4 time signature, Chramosta pounds through the heart of the band’s dreamscapes like Zach Hill from spastic Sacramento math-rock band Hella. His drumming style is refreshing in general, but, when placed behind a similarly complex tangle of memorable Gangi jams, it’s impossible not to get sucked in.

With an energetic post-punk repertoire and stage charisma to match, headliners The Happy Hollows proved to be the most universally appealing of the Eastside lineup. The Hollows’ technical skills and catchy riffs pleased not only its group of front-row regulars but even the large number of until-now confused male KROQ listeners — identified by their trucker hats and flip flops — who stumbled into the show through effective radio promotion.

It might also help that singer/guitarist Sarah Negahdari is an amazing performer, not just with guitar playing — which sometimes finds both her hands dancing on the fretboard — or singing — which often drifts into heavy panting and even meow-ing — but also with an adorably bipolar stage persona that hangs somewhere between cute, sexy and intense.

Between songs, Negahdari is almost unbearably nice. Emanating shy-girl sweetness, she wears an ear-to-ear Christmas-morning smile and genuinely thanks the audience for coming as if it were her wedding day. But when playing her guitar, Negahdari transforms from the meek girl behind the microphone to the unpredictable front woman of The Happy Hallows.

With her mind lost in music, she plays: Negahdari’s body fitfully flails around the stage during fierce moments and goes into a stoic, religious-like trance for softer ones. Swinging around sweat-filled hair one minute and politely tossing her pick into the audience the next, her energy evokes a more innocent, less ostentatious version of Yeah Yeah Yeahs singer Karen O if she took lessons from Grace Slick and a Kewpie doll.

Despite memorable sets by the other bands on the bill, of all the “locals only” acts playing the Viper Room that night, The Happy Hollows and its three-piece pop-rock beats had the most widespread appeal. Their upbeat ’90s alt-rock throwbacks effortlessly embraced the culturally diverse music listeners in attendance and had the entire Viper Room smiling as wide as Negahdari’s mid-song grins.

When “East meets West” in the Los Angeles’ music scene, good things are bound to happen.