The Arcade Fire: The band played free shows for Barack Obama.

On the eve of perhaps the most important primary election ever for most of the young adults in attendance, the Arcade Fire was determined to make an impression. Largely considered a Canadian band (the principal members are actually American citizens), the Arcade Fire made an 11th-hour stop at the Beachland Ballroom for a pair of shows to drum up support for Barack Obama.

With only half the band there (Win and Will Butler, Régine Chassagne, Jeremy Gara and Sarah Neufeld), the Arcade Fire prepared two nearly identical hour-long sets, playing the first for campaign volunteers and queuing fans, and the second for those lucky enough to receive tickets from the Service Employees International Union. The two sets, however, while similar in song selection, were different in delivery. The earlier one was more subdued, opening with a stirring cover of David Bowie's "Heroes," then working through some of the band's epic numbers. With Win doing his best to excite the crowd, urging everyone to vote, he explained that the band traveled 16 hours to "share our energy with you tonight and be here with you during this important election." It wasn't overly preachy and seemed to genuinely resonate with those in attendance, but while the words were lasting, the songs were more so.

Something happened, though, from the time Arcade Fire ended the first set and began the second. With another 500 people shuffling into the ballroom, from the first notes of set two, the band was determined to do something special. After covering Sam Cooke's politically charged "Change is Gonna Come," the band took its music to another level. Win performed all of "Rebellion (Lies)" in the crowd with his guitar raised over his head as he bellowed out the lyrics shoulder-to-shoulder with fans. "Neighborhood #3 (Power Out)" stretched for nearly 10 minutes, with the entire band working the crowd into a hot, frenzied sweat. The night then ended with an unplugged rendition of "Wake Up," as the band played without microphones and amps, urging everyone to vote and volunteer before finally leaving the stage.

Nellie McKay

Nighttown, Thursday, March 6

There's something to be said about the classic jazz club setting. Intimate, dark and crowded, Nighttown's jazz room provided the perfect venue for Nellie McKay's charming, humorous 100-minute set. Dressed in a red and black flannel dress, McKay made her way through the standing-room-only crowd, apologizing for being late, then taking her seat at the grand piano. Accompanied by Nighttown regulars Roy King on drums and Marty Block on upright bass, McKay enchanted the attentive audience, taking requests, chatting with the tables closest to her, and sticking around after the show to talk with fans.

Part of McKay's charm is her wicked sense of humor. Her jazz-pop arsenal showcases McKay's Broadway vocal range, but where she excels is in surprise laughs. A spoken-word rap-like "Identity Theft" was only played because an anxious fan provided McKay (upon her request) with the liner notes to Obligatory Villager. Then, during the ukulele ditty "Mother of Pearl," she started and stopped more than once, fumbling through a few lines of lyrics and commenting, "How can I forget my child molestation joke?"

But McKay is a musician and vocalist first, and throughout the night she spent time performing without the provided musicians, instead just tickling the piano to provide the only instrumentation, as she did on the scampering "Dog Song." As the show started to wind down, McKay engaged the audience, softly talking to those seated around her, and the final three songs of the main set, "Glaad," "Livin" and "David," were all played by request. After unnecessarily running through the crowd and back, McKay returned to her piano bench for a two-song encore of "Pounce" and "Work Song," the latter of which was punctuated by a group primal scream, brought about at McKay's lively urging. - AM

Black Mountain

Grog Shop, Thursday, March 6

Black Mountain took the stage around 11 p.m. and dove head-first into a set of psychedelic nu-Sabbath shenanigans, complete with a light show modified for a Grog-size arena. Lead vocalist Amber Webber conjured up the spirit of Grace Slick of Jefferson Airplane with her low, stammering siren drone. More than once I expected her to break into "Somebody to Love" mid-song. The appeal of Black Mountain is fairly obvious. Its sound evokes the aforementioned Black Sabbath and Pink Floyd as it's epic, dark and immersing: porridge-thick stoner-rock with a trendier haircut. The audience it drew at the Grog was expectedly dude-centric, with every type of male stoner represented. Not to say Black Mountain doesn't stand on its own without herbal assistance. Let's just say the key to the band's success probably lies not in the eyes of the beholder, but in the hands of those who are holdin'.

Nordic Nomadic opened with a short set that was pleasant enough and slightly psych in that special, fuzzy way that only a one-man band can be. There were some grunge-rock shades to his voice that didn't quite synchronize with his overall sound, however. The real stage stealer was Bon Iver, who released a stellar disc on the Jagjaguwar label last month. Justin Vernon's unnaturally high voice paired with minimal backing and a sparse, heavy bass drum made for an engrossing set that was by turns achingly sweet and powerful in a loud, masculine way. During an extended rendition of "The Wolves," Bon Iver's drummer finally got his chance to go apeshit on his kit while the third man onstage provided an additional bass drum. With Vernon's eerie, sweet vocals cresting over the percussive cacophony, I don't think there was anyone in the audience who didn't experience that song in a very deep, real way. It was far more emotionally engaging that anything Black Mountain offered up later that evening. - Emily Anderson