BRIDGEPORT, Conn. — What happens when 15,000 nomadic, hippie music fans converge on a beachfront park in 90-degree heat for more than 40 hours of jamming with little or no police presence?

A lot of music and a little hackeysack, but not much trouble — save for some inbound-traffic congestion and the occasional case of dehydration. The fifth annual Gathering of the Vibes festival went off without a hitch this past weekend, marked by warm temperatures and a party atmosphere that began early Friday evening and lasted well into the wee hours of Monday morning.

The tightly woven, heavy funk of Soulive and Connecticut's own Deep Banana Blackout jump-started the concert's festive vibe Friday.

"At first, we didn't know how we would be received at these kinds of Grateful Dead–type festivals," Deep Banana Blackout guitarist Fuzz (born James Sangiovanni) said, "but the people seem to like the funk we bring, and that's the common denominator."

John Scofield also explored the boundaries of jazz-funk during his Saturday afternoon set, which included the funk-infused "Blackout," from the March-released Bump, and the low-profile funk of "Jeep on 35."

"Absolutely, I can feel a difference between last year and this year," Scofield said following his second annual appearance at the Vibes. “The kids were really into it. They were already sold on the material from the A Go Go record, I think, so they knew about me and were into this stuff, too.”

Acres Of Tans, Tents And Twentysomethings

The scantily clad crowd of tan twentysomethings was sprinkled around Seaside Park's 370 sun-soaked acres. Tents selling T-shirts, grilled Mediterranean burritos, hemp clothing, skateboards and other items encircled the concert field. A maze of tents packed the campground, where even more party goods were traded and sold.

A truck holding a large water tank was anchored near the center of the concert field, spraying concert-goers with water throughout the weekend in an attempt to beat the simmering heat and humidity or perhaps to cleanse those who had mistakenly danced too close to the numerous banks of Port-O-Lets.

Primus bassist Les Claypool, along with keyboardist Jeff Chimenti and drummer Jay Lane of Ratdog, appeased the groove-hungry dance crowd Saturday night, playing under the name Rat Brigade. The band sifted through Primus covers and club-ready funk instrumentals, during which Claypool toyed with the classic bassline of the Sugar Hill Gang's "Rapper's Delight." The animated bassist then introduced Ratdog frontman Bob Weir as "Edward Van Halen" and later "Jimmy Page" as the ex–Grateful Dead guitarist joined the band for a closing cover of the Beatles' "Tomorrow Never Knows."

As he was setting up for the evening's final set, Ratdog bassist Rob Wasserman tinkered with the bass loop Claypool had ended on before exiting the adjacent stage. When Claypool returned, the two bassists exchanged solos on adjoining stages as Weir and Ratdog completed their setup and segued the jam into the Dead-show staples "Jack Straw" (RealAudio excerpt of the Grateful Dead version) and "Bird Song." Claypool, introduced by Weir as "Paul McCartney," eventually joined the band for "That's It for the Other One."

"It was cool that [Weir] agreed to play a show like this," 24-year-old Colorado fan Bill Donahue said, "because, for a while, at least, he didn't play Dead-head festivals after [Dead frontman Jerry]Garcia passed away."

It's About The Music, Not The Shirts

Claypool's recent collaboration with Phish guitarist Trey Anastasio and ex–Police drummer Stewart Copeland in the trio Oysterhead has been embraced by the jam-band scene.

"I'm just grateful there's people out there who want to hear you play and don't care about what color your shirt is or what hat you're wearing. They care about the music, and it's cool," Claypool said before his set. "The Oysterhead show really opened my eyes."

Another festival highlight for many was a midday set on Sunday by New Hampshire's Percy Hill. Donning the bright orange jumpsuits worn by the festival's recycling crew, the band crossed vintage disco and improvised funk rhythms with sun-drenched harmonies à la Steely Dan. Included were the peaking opener, "Ammonium Maze," and funk-driven "Soul Sister." Keyboardist Nate Wilson's spaced-out synth effects electrified the growing crowd during "Slave (Self-Promoted)" from the band's recent Jammy-winning Color in Bloom.

"Percy Hill gets an 'A' for keyboard effects," Chaz Korchinski, 23, of Fairfield, Conn., said. "They have that improvising '70s stuff and some of the whacked-out Dr. Dre–effects sh-- going on, too."

Down-home bluesman Walter "Wolfman" Washington, Atlanta acid-jazz improvisers Sector 9 and jazz-mandolin pioneer David Grisman also were among the weekend's most popular performers.

Jam-Band Scene Sprouts Legs

"The jam-band scene has grown so much since the first Gathering; it really seems to have found legs on its own," 29-year-old Strangefolk guitarist Jon Trafton said. "And the festival now seems to be a reflection of the diversity that's out there."

"Until recently, jam-band festivals such as the Vibes had been given little or no media attention," Strangefolk singer/guitarist Reid Genauer said, following the band's set, referring to camera crews from mainstream music outlets on hand to interview festival artists. "Now it's like, whether they like it or not, it's happening. The term 'jam band' has come to mean a lot of stuff — hip-hop, funk, you know. It's an actual genre of music, and I think that's cool."