But Chesney wasn't about to let the festivities wind down on this stop of his Poets and Pirates Tour.

"Thank you so much for letting us join the party," he told the crowd of more than 50,000, as if he'd wandered in from the parking lot while looking for a good time.

Good times are to Chesney what lawbreaking was to Johnny Cash, or heartbreak to Patsy Cline. Over the course of two hours and two dozen songs, Chesney never went more than a few minutes without referencing the joys of letting loose, usually with the aid of a handy six-pack.

Such mindful devotion to mindless indulgence is bound to exhaust the available material, and even Nashville's finest songwriters haven't been able to prevent Chesney's keg from running dry. "Everything is hotter when the sun goes down" sounds less like a call to all-night partying than the slogan for a tropical resort. Framed by beer-company banners, Chesney's concert came off as one big lifestyle ad.

With the help of a dozen musicians, including a four-piece horn section and a steel drummer, Chesney flavored his easygoing anthems with touches of ska and calypso, mixed with guitar solos out of 1970s album rock.

Although he's nominally a country artist (you could tell by the muscle shirt and cowboy hat he wore on stage), Chesney's the musical equivalent of the guy with the lamp shade on his head. He'll do anything if people seem to like it enough.

His dogged desire to please has paid dividends: more than 25 million albums sold and four consecutive awards for Entertainer of the Year from the Academy of Country Music.

But when Chesney reminisced about the songs of his youth in "I Go Back," it clarified what's missing from his own songs. The pungent details of John Mellencamp's "Jack and Diane" handily eclipse "Shiftwork," a vague blue-collar anthem Chesney dedicated to people who "work for a living." Sorry, trust-fund Chesney fans.

Keith Urban, whose alcohol-related rehab stays have been tabloid fodder for several years, steered clear of party anthems, although he did give a shout-out to the designated drivers in the crowd. Less than two weeks after the birth of Urban's first daughter, his songs about weathering turmoil and making the best of second chances seemed to have gained extra weight, though not enough to interfere with their feather-light construction.

In the post-alternative era, the banished cliches of stadium rock found a new home in the country arena, which is why it was only slightly odd to see Sammy Hagar amid the big-hat crowd. Dressed in performance sandals and plaid cargo shorts, Hagar looked like an aging beach bum. He even set up his own onstage tiki bar. But the music was pure '80s metal, a version of Toby Keith's "I Love This Bar" notwithstanding. A little of Hagar's party-boy scream goes a long way, but not nearly long enough to sustain an hour-long set.

Leann Rimes' songs are nearly as single-minded as Chesney's. She sings about being in love, looking for love, and getting over love, all with the same soaring voice. As a teenager, Rimes was bruited as the heir to Patsy Cline, but when she sang a few bars of her first hit, "Blue," rearranged as cocktail jazz, the heartbreak never pierced to her core.

Rimes' voice is an astonishing instrument, but it's as malleable as plastic, and about as soulful.