This was a weekend of jazz with strings at the JVC Jazz Festival and Vision Festival. Two of the greatest jazz violinists of all time, Billy Bang and Leroy Jenkins, headlined at Vision on Saturday, and a legendary guitarist, Les Paul, was feted at JVC on Sunday.

It was also a weekend of jazz and world music fusions. Mr. Bang performed with his Vietnamese ensemble on Saturday, and for three nights, the Jazz Standard presented the great tenor saxophonist David Murray with the Gwo Ka Masters from Guadeloupe.

Finally, this was a weekend of great jazz improvisors who know how to reach a large pop audience. Mr. Paul did this 50 years ago with his very successful string of voice-and-guitar singles co-starring his then-wife, singer Mary Ford. Mr. Murray seems to be doing that with the Gwo Ka Masters.

The penultimate night of Vision Festival X began with two exceptional violinists, Mr. Bang and Mr. Jenkins, in two very different contexts. Mr. Bang, who opposed the Vietnam War 40 years ago, has just released “Vietnam: Reflections” (Justin Time 212-2), his second album that explores his own history and attempts to blend jazz and traditional Vietnamese music.

Mr. Bang’s quartet at Vision – a smaller group than on the album – featured himself and bassist Todd Nicholson as well as two Asian musicians, trap drummer Shoji Hano and Ngo Thanh Nahn playing the dan tranh, a traditional Vietnamese instrument that resembles a large zither played with mallets.

The foursome started slowly, with the drums and the dan tranh playing what seemed like random notes. After a long while, Mr. Nicholson joined in, and finally Mr. Bang. The violinist then rewarded our patience with some of his most exuberant playing, jumping all over the stage and bowing and swaying like a Cab Calloway of the avant-garde violin.

Just as he took forever to get started, Mr. Bang treated us to an ecstatic climax that also seemed to defy time and last forever. His whole set was essentially this one piece – which, he told us, he has yet to title but referred to as “IWS,” which stands for “improvisation with structure.” For a brief encore, both the Asian and the American contingent got together in a funky blues riff.

Following Mr. Bang’s show-stopping turn, Mr. Jenkins played in support of dancer Felicia Norton. This was clearly a visual presentation, with Mr. Jenkins playing mostly long arco drones. The Angel Orensanz Foundation is a former synagogue, and the sight of this beautiful blond woman, dressed in a toga, dancing in front of the ark of the temple was somewhat surreal.

The last act I caught at Vision was the exceptional trumpeter Eddie Gale, best known for his work with Cecil Taylor, with a sextet of free jazz players all new to me: Ismael Navarette (tenor and soprano saxophone), John Gruntfest (alto), Valerie Mih (piano), and T. Squire Holman (drums). The bassist, William Parker, is one of the central figures of the festival and the current “avant-jazz” scene in general.

I’m not sure if it’s a compliment to describe an avant-garde group as “listenable,” but Mr. Gale’s group was: a very user-friendly 1960s-based blend of free jazz and modal techniques with two tunes dedicated to Miles Davis and John Coltrane. Mr. Gale did two albums of his own for Blue Note in 1968 and 1969, and both deserve to be better known – just as this current group deserves to be recorded.

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On Sunday at Carnegie, one of the best-known musicians in the world, the guitarist and electronics pioneer Les Paul, was celebrated on the occasion of his 90th birthday. The concert, like Mr. Paul’s career, was a decidedly mixed bag.

The first half, with several notable exceptions, was unbearable. A parade of blues rock guitarists, each worse than the one before, got up and paraded by in an exercise in anti-virtuosity – the “American Idol” school of singing as applied to the electric guitar. Only two players were not doing a horrendous caricature of Mississippi-Chicago bluesmen. The only African-American on the bill, Stanley Jordan, played a thoughtful and melodic classical piece (vaguely Schubertian) using his tapping technique. The Australian Tommy Emmanuel, meanwhile, playing acoustically, treated us to a South African showpiece.

At a tribute to Doc Cheatham last week, producer Chuck Folds made sure that everyone at least played songs associated with the late trumpeter. Here no one seemed to have even heard a Les Paul record. Fortunately, however, he was present in person to rectify that. And the second half, which starred the man of the hour himself, was considerably better.

This jazz portion of the evening featured first-rate playing from Pat Martino (whose “Sunny” here was less dense than his usual playing) and Bucky Pizzarelli (on an elegant “Nuage”).Yet no one pulled focus from the birthday boy, who was quick to knock us all on our collective cans with a wisecrack when he wasn’t soloing (as on “Brazil” and a medley of “I Can’t Get Started” and “Lazy River,” which quoted liberally from “Peg O’ My Heart”). The second half wasn’t without its pitfalls – two prodigies, guitarist Butch Trucks and singer Madeline Peyroux, merely seemed overwhelmed, and Jose Feliciano showed wasted time with a longish solo production number. But at least we walked out of Carnegie with a tune on our lips.

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From Friday to Sunday, David Murray held forth with the Gwo-Ka Masters at the Jazz Standard, his capacious tenor working in conjunction with two Guadeloupian percussionists, fender bass, electric guitar, and American trap drums. The combination of Mr. Murray’s massive sound and the dance rhythms of the islanders (as heard on “Gwotet,” Justin Time 200) is absolutely irresistible.

Mr. Murray has found his own completely personal answer to Sonny Rollins’s jazz calypsos and Monty Alexander’s jazz-reggae fusions. This is a David Murray band that should play bigger stages at JVC, not to mention ballrooms and other dance venues. I was also grateful that catching Mr. Murray’s 7:30 set at Jazz Standard allowed me to avoid a couple of the rock guitarists at Carnegie.