How perfect were the weather, setting and (not to be underestimated in this case) beer concessions at the Rock the Garden concert Saturday outside the Walker Art Center? Perfect enough for a schlocky, syrupy, fairy-tale-fringed rock opera to go over like it was fireworks on the Fourth of July.

Against many odds, the Decemberists finished off the sixth almost-annual museum soirée on a high -- and completely stonerish -- note with their conceptual 17-part rock opera, "The Hazards of Love." The lofty, frilly and really utterly ridiculous hourlong piece of music was met with a surprisingly enthusiastic response from the sold-out crowd of nearly 10,000 music fans.

Some of the surreal scenery from the "Hazards" rollout included a sea of fists pumping in the air Judas Priest-style during the "Margaret in the Taiga" portion of the program, during which guest singer Becky Stark (playing the role of Margaret) swayed around in a billowy white princess dress. Meanwhile, nerdy frontman Colin Meloy slung his guitar throughout the set like Ted Nugent dressed in an undertaker's uniform. Toward the end, fans feigned munchkin dances as a prerecorded children's choir pumped through the speakers in "The Hazards of Love 3 (Revenge!)."

Some of the music in the Decemberists' opus genuinely matched the ambition. During "The Queen's Rebuke," the band got ace support from second guest singer Shara Worden of My Brightest Diamond, who wore a slinky black dress. (Get it? Black dress/white dress = good vs. evil).

Worden and Stark reclaimed the spotlight when the band encored with a cover of Heart's "Crazy on You." Coupled with the burning version of Love's "Alone Again Or" earlier in the night by eclectic Arizona band Calexico, the classic-rock side of this Garden party made it strangely akin to Taste of Minnesota.

Finally, after years of being staged in the street, Rock the Garden was staged in an area as picturesque as Taste: not the actual sculpture garden it's named for, but a grassy hill where the Guthrie used to stand, now a natural amphitheater.

The setting made for many more picture-perfect moments, like when the sunset tangled with cloud cover as Calexico's Mexican mariachi horns and tumbleweed-paced songs provided a spaghetti-western soundtrack. A sign of just how loosely Calexico defines (and reinvents) Americana music, the group's other cover song of the night was a psychedelic-roadhouse version of the Minutemen's "Jesus & Tequila."

Before Calexico, New York's collage-art-rock band Yeasayer turned the Garden party into a dance party with "2080," a favorite on RTG co-sponsor the Current (89.3 FM). Its hit aside, though, Yeasayer's set was mostly a messy pile-up of off-tune falsetto vocals running up against two competing percussionists and needle-prickly guitars. These guys simply try too hard.

The lone local act on the bill, Solid Gold, combined hometown pride with ecstatic dance beats and accessible pop melodies to bowl over both Calexico and Yeasayer. The fret-filled gems "Get Over It" and "Calm Down" burned under the hot sun like winter's misery burning off in four-minute bursts. And unlike the Decemberists, Solid Gold didn't have the six-hour effects of extra Summit beer stands to help its cause. • 612-673-4658