AUSTIN, Texas — These Volsung dudes could be huge some day. They sound exactly like Metallica.

Sorry, that was a bit of a South by Southwest in-joke. See, in the weeks leading up to SXSW 2009, the folks behind the fest tried to pull a fast one on fans, listing Volsung, a metal band from "Somewhere, Norway," in the 10 p.m. slot of the "Guitar Hero: Metallica" launch party.

It didn't take long for the speculation to start. It seemed most people believed that Volsung were, in fact, actually Metallica, and as SXSW drew closer, the rumors of a full-blown performance began to swirl. The whispers grew into a roar when the "Guitar Hero" folks released a poster touting an appearance by "members of Metallica."

And it all came to a head Friday night at Stubb's, before a capacity crowd inside and an even bigger throng outside, mostly packed into a nearby parking garage, craning their necks to get a glimpse of the action. Then, just before 10 p.m., after opening sets by the Silversun Pickups and some dudes playing "Rock Band," the lights dimmed, the house speakers began to vibrate with the strains of an epic, Ennio Morricone instrumental, and lo and behold — Metallica appeared, live and in the flesh.

They didn't waste a second either, launching headlong into a scorching version of "Creeping Death" from 1984's Ride the Lightning, then power-shifting into a down and dirty take on "For Whom the Bell Tolls." Of course, pretty much everyone expected all of this to happen (at one point, frontman James Hetfield jokingly welcomed the audience to "the worst-kept secret in rock and roll"), but it didn't matter in the least: Fans inside — and out — went berserk, tossing devil horns, pumping fists and singing along to every word.

Feeding off that energy — and perhaps getting a kick out of playing what, for them, was basically a small club gig — Metallica never took the foot off the accelerator. For the next 90 minutes, they riffed hard and fast through classics like "Harvester of Sorrow," "Sad but True," "One" and (of course) "Master of Puppets." They implored the audience to "give us your best" (truly, no massively successful band pleads with the audience as much as Metallica do) and appeared to have an absolute blast, even when they were battling problems with the house equipment.

It was those rather imperfect moments — the odd dead mic, a detuned guitar or two — that gave the Stubb's gig a sort of underdog charm, no small feat when a band of Metallica's caliber is involved. And seemingly, even the band sensed it. Lars Ulrich traded banter with fans between songs, Robert Trujillo asked for a good place to grab some BBQ, and even the normally serious Kirk Hammett managed to crack a smile or two. But no one got it more than Hetfield, which probably explains why, before launching into "Harvester," he paused, cracked a smile and got into full Volsung character, telling the crowd, "Vee are a young, struggling bandt from Norvay, and vee vant to get signed."

James Hetfield doing impressions. You don't get that at your average Metallica gig.

It wasn't your average Metallica gig up the street at Club de Ville, either, though it certainly was just as packed. Rather, it was a grab-bag assortment of cutting-edge (read: Day-Glo Ray-Bans and DJs with MacBooks) hip-hop, featuring plenty of bleep-boop, and sets from pint-sized British MC Lady Sovereign, sassy Chi-Town rapper Kid Sister and — most notably — dunderheaded party master Asher Roth.

Currently riding high — pun intended — on the strength of his ode to intoxication "I Love College," Roth was the de facto headliner of the night (despite the fact that Kid Sister actually was), though it's entirely possible he was not aware of this. Flanked by a hypeman and backed by a nerdy DJ and a live drummer, he delivered a laconic, stoned-to-the-bone set, heavy on the weed humor ("Blunt Cruising") and crude double entendres ("Lark on My Go-Kart"), but it got the crowd jumping nonetheless.

While he might look like he just stumbled out of bed, Roth is no slacker. His rhymes are deft, funny and tight (even if he does sound an awful lot like Eminem), and he's got a wicked sense of humor too — as evidenced during a mid-set skit in which he flicked through a fictional mix CD and smoked an imaginary joint (which he passed to the audience).

Of course, he closed with "College," a subtly brilliant anthem that could make him a very big star (or at least earn him a lifetime of dorm-room gigs). He and his crew broke into a well-sequenced two-step shuffle, with huge, slightly stupid grins plastered across their faces. And though his jokey style and organic music might have stuck out like a pair of sore thumbs on this electro-heavy night, there's no denying that Roth was the biggest star on the entire bill. By a mile. Whether or not he chooses to seize the opportunities available to him remains to be seen.

But that's better left for another time ... after all, this was Friday night at SXSW. Metallica cracked jokes. Asher Roth was let loose in one of the biggest college towns in the U.S. Welcome to the weekend.

MTV News is Live & Mobile at the South by Southwest festival this week, with blogs, articles plus live and on-demand video of all the bands, gigs and BBQ!