The collective spirit that pervades indie music today generally manifests itself in large Canadian supergroups, guest glockenspielists and recombinant side projects, sometimes resulting in musical consequences bordering on the ridiculous. The San Francisco-based artist John Vanderslice, who played the Middle East Upstairs Friday, is not generally associated with this tomfoolery. He did, however, put on an excellent show featuring a revolving (stage) door of guests, including audience members and instrumentalists with whom he had not rehearsed.

Vanderslice played new songs-from his album due Aug. 7-in between lengthy breaks during which the Middle East's sound engineers fiddled with the various microphones and cables. Vanderslice's voice remained strong throughout his lengthy-almost two hours-set, made longer by all the technical difficulties. During the breaks, Vanderslice gave shoutouts to his tour manager and set up the songs, bringing onstage the local singer-songwriter Elijah Wyman for an acoustic version of "Wild Strawberries," from Vanderslice's 2004 album Cellar Door, on a lap dulcimer; a fan named Carson to sing lead vocals on "Letter To The East Coast," from his 2005 album Pixel Revolt; and a whole chorus of audience members to play tambourine and sing backup vocals for "Me and My 424,"from the same album.

The crowd seemed mainly interested in songs from Pixel Revolt, but there were a couple of very vocal fans of older material, including one who was intent on requesting the controversial "Bill Gates Must Die," which Vanderslice released in 2000 shortly after the breakup of his former band, mk Ultra.

After the big audience jam-fest of "Me and My 424," Vanderslice convinced the sound men to play loud rap music over the house speakers and said, "It's only 12:30; let's have a dance party!" energizing the still-attentive audience, an hour and a half after the beginning of his set.

Opener St. Vincent (aka, Annie Clark) made the most of the effects pedals and microphones currently in vogue, using a second microphone that made her voice sound like an old radio broadcast and pedals that changed her sound from calypso to electric guitar to other effects. Although Clark's voice is less idiosyncratic than other popular female indie troubadours like Leslie Feist, her engaging stage manner and wry humor made her show more than just a recital of her macabre ballads and timeless, jazz-influenced songs. The highlight of Clark's performance, however, was her cover of Nico's classic "These Days," which appears on St. Vincent's EP Paris is Burning.

The adorable quotient was fulfilled near the beginning of the evening, when Clark called an audience member onstage after performing her new song "Marry Me," which the audience member then sang a little bit before proposing to his wife, who was also in the audience. InI hadn't listened to much of Clark's music before the show, and I was genuinely impressed by her performance.

The solid performances by both Clark and Vanderslice were enough to win over even the most skeptical fan. Vanderslice promised to return in the fall; his booking agent had considered a show at Brandeis this spring. Here's to John Vanderslice in Waltham next semester.