GREAT BARRINGTON, Mass. — The three-day Berkshire Mountain Music Festival — which brought a traffic jam of about 9,000 people to the Butternut Ski Basin for a rain-soaked opening night — ended early Monday morning with burning and looting.

Sorry, make that Burnin' & Lootin', a Bob Marley tribute band that brought Berkfest to a fitting late-night close, with surprise guest guitarist Vernon Reid joining drummer Bob Moses, DJ Logic, singers Dan Rockett and Ekene Nwokoye, and members of Soulive, Jiggle and String Cheese Incident. Reid and Soulive's Eric Krasno traded biting flurries, and even jazz eccentric Moses' teenage son added a couple of raps.

Far from the afterburn of Woodstock '99, mellow vibes ruled the neo-hippie crowd, which wandered among the five stages of the hilly site. And Burnin' & Lootin' provided the capstone to a weekend filled with spontaneous collaborations and intriguing cover songs.

The hottest main-stage collaborations took place Saturday evening, after Friday's rains — which forced Afro-pop star Femi Kuti to one of the two indoor stages —dissipated into cool, comfortable and only sporadically damp weather.

Béla Fleck & the Flecktones, led by banjo ace Fleck, delivered one of the weekend's most invigorating sets, especially when DJ Logic lent turntable scratching and space effects to the group's fresh take on Aaron Copland's "Hoedown" (RealAudio excerpt). Mixing old-school instruments once considered bizarre for jazz fusion, on a classical piece yet (with a slight nod to Emerson, Lake & Palmer's prog-rock version of "Hoedown"), Fleck and Logic shared an open-minded vision for music in the new millennium.

Flecktones' percussionist Future Man likewise introduced the finger-triggered beats of his invention, the Synth-Axe Drumitar, to new converts in the festival crowd, while Jeff Coffin emerged as a more confident voice, blowing foghorn harmonies simultaneously on alto and tenor saxes à la Rahsaan Roland Kirk. Returning to earth, the Flecktones huddled around one mic to sing "Polka on the Banjo" while bassist Victor Wooten's 2-year-old daughter danced along.

The mix-and-match mania continued with moe., who took time out from recording to play Berkfest (a warm-up to moe.down, a similar festival Labor Day weekend in Turin, N.Y.), and seemed rusty on opener "Godzilla." But that Blue Öyster Cult cover set the tone for a heavy, lighting-enhanced set that peaked when Coffin, Future Man (on cowbells and timbales) and Logic added textures to lashing, across-the-map jams, culminating in a long "Timmy Tucker" and "Recreational Chemistry" that overcame a brief power loss with a still-raging drum break.

Strong Cheese, Deep Bananas

String Cheese Incident had the biggest presence, however, playing all three days of the fest, including a Saturday union with occasional ally Keller Williams in which they traveled through dreamier terrain behind his 10-string acoustic leads before rendering a spot-on cover of the Grateful Dead's "Franklin's Tower."

String Cheese's laid-back flow is quite reminiscent of the Dead, but the Colorado band, in its own eclectic set Sunday, went from "Latinissimo" (fueled by Michael Travis' feisty mix of kit and hand drums) into the bluegrass romp "Mountain Girls."

Still, energetic funk provided most of the flow Sunday with main-stage workouts by Galactic and Deep Banana Blackout. Galactic married New Orleans groove and acid-jazz jams with sharply etched angles, finding tonal convergence in Rich Vogal's organ and Roger Lewis' baritone sax. Then orange-suited singer Theryl de Clouet stepped out to give funkier weight, including a gruff, voodoo-styled twist on Black Sabbath's "Sweet Leaf."

In turn, Deep Banana Blackout took advantage of emotional energy from singer Jen Durkin's last performance with the band (she'll dabble in solo work while the 8-piece group continues with another singer). Bounding about an orange miniskirt, egged on by the band's buoyant horns and Fuzzy's stinging guitar, Durkin reached a Janis Joplin-esque fervor that had fans pogoing in place for old DBB favorite "The Groove Is Here."

Eclectic Selection

Alas, after Sunday's high-energy sets on the main stage, headliner Medeski Martin & Wood seemed a bit sluggish and inward-minded, largely improvising jazz-funk grooves that deserved more melodic development than John Medeski's choppy clavinet motifs delivered. Late to start, the trio also got cut off by a curfew before they could have mentor Bob Moses sit in.

If MM&W represent the forefront of the jazz-meets-jam trend, they had competition from bands on Berkfest's other stages, especially two stages alternating on a sundeck by the sprawling parking lot. The Slip displayed more sonic change-ups than in the past, with Brad Barr lending sitar guitar to an African-tinged "Cumulus." The Fully Celebrated Orchestra went for more full-bore, small-combo jazz in the tradition of Ornette Coleman, the Art Ensemble of Chicago or Masada, wielding rhythmic chops that went beyond groove. Ray's Music Exchange, from Cincinnati, worked more of a balance in that direction, while a condensed new edition of Viperhouse delved into techno-fusion as well as Ellington.

Straight-ahead bluegrass could be found in bands such as the heavenly Yonder Mountain String Band and the surprising Acoustic Syndicate, as well as Fleck sitting in with Peter Rowan, but world-music sounds also infiltrated jam-land. Perhaps the weekend's most stirring discovery was the ethnic-techno-rock of Balkan Tribes, a Boston-based group with members from different regions of the war-torn former Yugoslavia, fronted by bewitching vocalist Alma Vucinic.

Jiggle, formerly Jiggle the Handle, won the weekend's cover-song sweepstakes by devoting one of its three Berkfest sets to Paul Simon's Graceland in its entirety, with bookends of songs by Pink Floyd, Phish — whose "Rift" is not the easiest number to pull off — and the Beatles.

"I like when bands do covers," said Vivek Sikri, 25, of Boston, sporting a T-shirt from one of Phish's campout fests, "because it helped me to get into their styles."

Certainly it was hard to sample and appreciate everything that was going on, but only Joules Graves fit the hippie stereotype, singing songs about celebrating the earth and fighting violence, urging a side-stage crowd to get closer, saying "When we're close up, we can make it happen."

Beyond the traffic and rain, Berkfest had a lot of positive things happening in the ever-expanding valley of the jams.