Could there possibly be a more joyful place for listening and dancing — while the sun sets — than the aptly named Spirit of Music Garden in Grant Park?

With top-notch musicians performing on a small stage, Chicagoans of every stripe swaying on a makeshift dance floor and non-hoofers listening from amid the foliage, the place has become a refuge from the rambunctious city that surrounds it.

More than that, the eighth annual Chicago SummerDance Series — which brings live concerts to the garden Thursdays through Saturdays (and disc jockeys on Wednesdays) — has emerged as a focal point for first-rate ethnic, world-music and other non-commercial attractions that don't get a fraction of the attention they deserve.

Jazz bands, mambo outfits, zydeco ensembles, barn-dance groups, Lithuanian folklorists — they all play here eventually, though few embrace as many musical languages as the septet that swung the garden on Thursday evening.

By calling themselves Les Yeux Noirs, after the vintage tune "The Black Eyes," the Paris-based band alludes to its fascination with Gypsy music, but that's just a starting point. Add elements of Jewish klezmer, mainstream jazz-swing and classic French chanson, and you understand the sonic building blocks of this stylistically uninhibited organization.

At its center are the French violinists Eric and Olivier Slabiak, brothers who established Les Yeux Noirs about a decade ago and put their classical training to excellent use. Their silken virtuosity, impeccable pitch and warmly radiant tone clearly inspire everyone else in the band to aspire to a comparable level of musicianship.

Considering how much sloppy musicmaking and unfortunate technique has been merchandised in recent years under the rubrics of "eclectic," "world music" and "klezmer," Les Yeux Noirs comes as a refreshing change of pace — the musicians actually can play.

In the course of a single set, such as Thursday night's opener, the band traversed ancient Hebraic melodies, classic Gypsy dances and even funk-tinged instrumentals. The beauty lay in both the sophistication and the accessibility of this repertoire. For those inclined simply to dance, the buoyant dance rhythms do the job. For those who care to listen closely, the harmonic twists and turns transcend the usual, well-worn chord changes.

Restlessly switching from major to minor, from one exotic mode to another, Les Yeux Noirs revels in surprise. Even the dancers in the crowd, and there were many, had to be caught off guard by the inexorable changes in tempo and the sometimes abrupt shifts in backbeat.

When the brothers Slabiak offered duets, their intonation and tone were so sublimely matched that one might have thought a single, massive fiddle was at play. Eric Slabiak's gauzy vocals gave the proceedings a nocturnal ambience, while the sound of the cimbalom evoked Hungarian influences.

Judging by the audience response, the band could have played through the night without losing the crowd.

Chicago SummerDance in the Spirit of Music Garden, 601 S. Michigan Ave., features a different band at 7:30 p.m. every Thursday through Sunday (with dance lessons at 6 p.m.); and a deejay show at 6:30 p.m. every Wednesday. The series continues through Aug. 29; admission is free. For the complete schedule, phone 312-742-4007 or visit www.cityofchicago.org/CulturalAffairs/SummerDance.