As the premier head-banging shed tour of the year, Ozzfest was growing a little long in the tooth (or in the fangs, as the case may be) as it prepared to embark on its 12th trip cross- country this summer. That is, until Sharon Osbourne, the fest's driving force and the renowned Iron Maiden of heavy metal, came up with the idea of giving the tickets away for free.

"I'm not trying to be the Mother Teresa of the music industry, because I like money more than anybody else," Ozzy's spouse recently told Scripps Howard News Service. "[But] these kids cannot afford to keep shelling out all this money, every year charging more and more. The brakes have to come on somewhere."

To that end, Osbourne approached Michael Rapino, president of giant national concert promoters Live Nation, and suggested giving the tickets away. "He said, 'We might as well -- nobody's making any money here,'" Osbourne recalled. "So that's what we did: We found sponsors to come in and underwrite the running part, and we found bands who just want the stage -- they just want to perform."

Long one of the most shrewd and canny entrepreneurs in the rock world, Osbourne seems to have succeeded in injecting new life into the fest, keeping the franchise alive and also assuring big crowds as her hubby performs songs from a recent album representing his first new studio material in six years. In fact, Scott Gelman of Chicago's Live Nation office told me the promoter expects capacity crowds at this weekend's shows at the First Midwest Bank Amphitheatre in Tinley Park and Alpine Valley in East Troy, Wis., making them two of a handful of shows to fill those venues this season.

"It's a unique and obviously very different idea, and nobody's really done it on this scale before, putting a major tour out there for free," Gelman said. "It's a learning curve for everybody to see how the economics work, but we're all going to learn and figure out how to do this in the future."

So we may see more free summer arena shows in the future?

"Obviously, there's a cost associated with it," Gelman said, "but if we figure out a way to underwrite that -- why not?"

Whether the free Ozzfest will come to be viewed as the first in a welcome trend or a noble experiment that left everyone poorer but wiser remains to be seen. Meanwhile, here's a look at the acts on this year's bill, comprising a typical (for this fest) mix of mainstream and underground metal, and the best bargain of 2007.

 

The doddering but lovable legend of metal -- star of stage and screen, and notorious tormentor of innocent winged creatures -- didn't pack much of that vintage wallop on his recent album, "Black Rain." But longtime fans put off by the soggy ballads and generic rumble shouldn't fear, since our hero has been only playing a handful of the new songs in concert. Comprising most of his set are the expected hits from his early solo career (tunes such as "Mr. Crowley" and "Crazy Train," which never get tired) and a few Black Sabbath tunes tossed in at the encore (which, while never as good without Tony Iommi and Geezer Butler, certainly never get old, either).

 

Straddling the line between progressive rock and thrash metal, this quintet from Richmond, Va., is one of the most innovative acts in the current metal underground, with philosophical lyrics about religion, politics and the ills of society that are nearly as heavy as the music on its four albums, including the latest, "Sacrament" (2006).

 

Along with the distinctions of having the best hair on Ozzfest (courtesy of guitarist-vocalist Wayne Static) and owing its origin to Billy Corgan (who introduced the band members when they were sharing a rehearsal space with Smashing Pumpkins), Static-X is another of the more distinctive groups on this year's lineup, bringing elements of industrial music into its particular take on metallic grind, as evidenced by its fifth album, "Cannibal," released last April.

 

Every era has its Gwar -- or its Alice Cooper, if you prefer to reach a bit further back in history -- and Lordi is the over-the-top spectacular/theatrical rock band of the moment. A bunch of goobers from Finland led by one Tomi Putaansuu (that's "Mr. Lordi" to the faithful), they dress in silly costumes and play even sillier music, including "Hard Rock Hallelujah," the single that made them famous by winning the 2006 Eurovision Song Contest.

 

As always, Ozzfest's smaller secondary platforms are where some of the harshest, edgiest and most forward-looking clang and clatter rules, and a few of this year's performers are even strong enough to offset the horrible location of this stage in one of the First Midwest Bank Amphitheatre's inhospitable asphalt parking lots.

In the order listed on the Ozz- fest Web site, the second-stage acts include Hatebreed, the mosh-inducing hard-core punk band from Connecticut; Behemoth, melodic and atmospheric black metal from Poland; DevilDriver, a self-described "death metal/groove band" from Santa Barbara, Calif., that recently replaced Nick Oliveri and Mondo Generator on the bill; Nile, old-school death metal from South Carolina, and Ankla, a Los Angeles metalcore band led by former Puya guitarist Ramon Orti.

Also: Circus Diablo, generic alternative rock from L.A.; the Showdown, a Christian metalcore/Southern rock band from rural Tennessee; 3 Inches of Blood, a charmingly named power metal band from Vancouver fond of Dungeons & Dragons-type fantasy lyrics; Chthonic, black metal meets the sounds and themes of the ancient East in Taiwan; Daath, extreme metal from a Georgia sextet, and In This Moment, a metalcore band from L.A. that will bring a rare dose of estrogen to Ozzfest courtesy of vocalist Maria Brink.