Perhaps the highlight of the Guinness Fleadh on Saturday on Randalls Island came at midday on one of the festival's smaller stages. There, backed only by an acoustic guitar, Tommy Makem bellowed a stentorian "Four Green Fields," the hallowed Irish leave-us-alone-with-our-beauty ballad he wrote in 1967, as the audience members pumped their hands in the air and sang in spellbound unison. Shortly afterward came the festival's low point: on the main stage, Hootie and the Blowfish — the very name may evoke a desire to yawn and move on to the next article — took "Black Magic Woman" on a journey that was too long, too bumpy and had no destination.
Mixing moments of musical transcendence with utter boredom has become a staple of the Guinness Fleadh, which in three years has grown from a precarious newcomer on the festival circuit to a welcome institution. Even when the music misses its mark — when the fiddle strings are cursed, as a speaker on one stage said, quoting W. B. Yeats — the festival still retains its charm. On Saturday the charm was that of a casual picnic as the day began and of a boisterous, friendly pub by nightfall.
Ending its four-city tour, the Irish (or, more accurately, Irish-theme) festival also featured performances on the main stage from Lucinda Williams, John Prine, Altan, the Eileen Ivers Band, Elvis Costello and, inducing the audience to its height of boisterousness, the Saw Doctors. The Fleadh (pronounced flah, the Gaelic word for festival) also included three smaller stages with music and spoken word, booths full of the kinds of clothes and crafts one regrets buying by day's end, and a number of exhibits put up by VH1 that had nothing to do with traditional Irish culture (like the synthesizer jam session and the memorabilia from divas like Whitney Houston).
Representing the more traditional side of Irish music were Altan as well as the Eileen Ivers Band. Ms. Ivers, a fiddler from Riverdance, was a gentle band leader, mixing bluegrass, classical, rock and even a little rap into her eclectic reels, the pinnacle of which was a percussion solo battle by the bongos, a drum kit and a tap dancer from Riverdance, Tarik Winston. Meanwhile on one of the small stages the popular and equally eclectic Irish American rock band Black 47 kept another tradition alive, protest, complaining that it was "not quite Riverdance enough to make it to the main stage," before going on to decry, in rap form, conditions in Northern Ireland.
Representing Irish rock on the main stage were the Saw Doctors, the Galway band that celebrates rural Irish life in a way that hits home, even with those who aren't expatriates longing to reconnect. The band played raucous, shout-along rock-and-roll with melodies and lyrics one can understand even when drunk. Choruses — about being friends to the end, meeting on Clare Island off the Irish coast and driving to the airport — were repeated as many as 40 times, sung louder and more emphatically until they transformed from simple rock-and-roll numbers to spittle-flying patriotic anthems.
Lucinda Williams played a strong set of twanging folk, country and rock dedicated mostly to places and people that have passed through her life — some benignly, others tragically — with Elvis Costello joining on guitar and backing vocals for two songs from her most recent album, Car Wheels on a Gravel Road.
John Prine, impeccably dressed in a black suit (befitting his status as one of the finest singer-songwriters of the last 30 years), came on like a dapper bard, full of poetic folk wisdom from his more recent albums. Returning to the stage after spending last year recovering from the removal of a malignant tumor in his neck, he sang with a voice that had grown more ragged, but delivered his lyrics with the laughing acuity (mixed with the occasional flash of wrenching empathy) that he has perfected, especially in a version of "Lake Marie" that was only improved by a broken guitar string.
Working on the transition from flash-in-the-pan pop stars to enduring road warriors, Hootie and the Blowfish has changed. The singer Darius Rucker was much more confident onstage, full of practiced dance moves, rump shaking and added vocal flourishes (including a pretty good imitation of Elvis Costello). The band, which was sometimes hard to hear over the woman nearby yelling "boring, boring, boring," covered what Mr. Rucker said was his favorite song of the 90's, the Stone Temple Pilots' "Interstate Love Song," dabbled with Lauryn Hill's "Doo Wop (That Thing)," and, overall, proved itself to be just good enough to be mediocre.
Topping the bill on the main stage was Mr. Costello. Ever reliable yet ever changing, he can always be expected to play certain songs live — "Alison," "Watching the Detectives," "Man Out of Time," "(What's So Funny 'Bout) Peace, Love and Understanding" — but never in a completely familiar version. For the Fleadh, he was accompanied only by Steve Nieve on piano as he played guitar, alternating, not unlike Neil Young but not unlike a lounge troubadour with a few tics either, between acoustic balladry and gales of distorted electric bravado.
On the smaller stages the Belfast band Watercress played roughshod rock with big pop sensibilities; Blink merged its pop-punk with fiddling; Martin Sexton stuffed as much emotion into his guitar and microphone as they could hold; Richard Thompson stunned in a less-wisecracking, more rocking guise, and Shane MacGowan closed the festival.
If the Saw Doctors played drinking songs, Mr. MacGowan played drunk songs, slurring through a caterwaulingly effective version of "Dirty Old Town" by his former band, the Pogues, as the crowd leaving after Mr. Costello's encores filed past him and through the exit.