Chicago promoter Mike Reed pulled off exactly that last year, when the event was called the Intonation Music Festival, and all signs point to this year's concert in Union Park being even better. Two-day passes are already sold- out, and the fest is likely to reach its maximum attendance of 15,000 fans per day before the gates even open -- a reasonable cap that will be far from over-crowded but an impressive success nonetheless.

Reed split from his former partners after Intonation I; Jon Singer and Mike Simons kept the original name and hosted their own successful event at the same site a few weeks ago. The theme of their bookings was an almost schizophrenic diversity. Reed and his media sponsors at the popular Pitchfork Webzine are more focused on indie rock on their two main stages, but there are still plenty of surprises and a few real coups.

Here is an hour-by-hour look at Pitchfork's mainstage lineup.

Saturday

1 p.m., Hot Machines: The music kicks off with this Chicago garage-rock trio, which is led by guitarist-vocalist Jered Gummere of the Ponys.

1:30 p.m., Chin Up Chin Up: Having endured the tragic death of their original bassist Chris Saathoff, this local avant-pop quartet went on to build a growing following with its debut album, 2004's "We Should Have Never Lived Like We Were Skyscrapers," and a 2005 EP.

2 p.m., Man Man: "Eclectic" and "eccentric" don't even begin to describe the music of Philadelphia's gonzo quintet, which is devoted to making Tom Waits at his weirdest and Captain Beefheart at his strangest seem as bland as Michael Bolton.

2:35 p.m., Band of Horses: Always fond of dreamy pop albums with just a hint of dark morbidity (see the Arcade Fire), Pitchfork loved "Everything All the Time," the Sub Pop debut from the new band formed by Ben Bridwell and Matt Brooke, formerly of Seattle's unimpressive Carissa's Wierd. I thought the disc was a mixed bag, with too much sleepy filler and generic jangle, but I'm eager to see what the group can do onstage.

3:30 p.m., Mountain Goats: Absurdly prolific (his Web site lists 449 songs to his credit), devoted to old-school lo-fi cassette recording and fond of sweeping, literary song cycles, Bloomington, Ind., native-turned-California resident John Darnielle finally graduated from the ranks of underground tape traders to 4AD Records a few years ago. His newest album, "Get Lonely," is due next month.

4:20 p.m., Destroyer: Destroyer is the perennial "other band" fronted by Dan Bejar, an indie-rock hero best known for his contributions to the New Pornographers. Vancouver's twisted power-pop songwriter recently released his seventh album in this guise, "Destroyer's Rubies."

5:10 p.m., Art Brut: England's long-running "Top of the Pops" may have come to an end without Art Brut getting its chance to perform on the show -- the reason it became a band -- but the quintet should be proud of releasing one of the best albums of 2006, "Bang Bang Rock & Roll" (originally issued in the U.K. last year). Hands down, Eddie Argos is one of the most captivating frontmen in rock today, and there's no question that this is Day One's best booking.

6:10 p.m., Ted Leo: This New Jersey native can be cloyingly over-earnest at times -- a thrift-store Bono of sorts. But the guitarist, vocalist and songwriter is always better appreciated live with his band, the Pharmacists, especially when they emphasize the energizing punk and avoid the folkie preaching.

7:10 p.m., The Walkmen: Formed by veterans of emo hypes Jonathan Fire Eater, New York's Walkmen pursue a more varied and sophisticated sound on their third album, "A Hundred Miles Off." It has built an indie buzz while also courting a mainstream breakthrough a la Death Cab for Cutie with a cameo on "The O.C."

8:10 p.m., The Futureheads: Kindred spirits of New Wave of New Wave Englishmen such as the Bloc Party and Franz Ferdinand, the Futureheads are touring in support of their just-issued second album, "News and Tributes."

9:10 p.m., Silver Jews: Songwriter, professor and poet David Berman has spent much of his musical career trying to escape the notion that his group is a Pavement side project -- despite his frequent collaborations with Stephen Malkmus and other Pavement players, and a similar love of arch irony and strange genre combinations -- while steadfastly avoiding live performance. This rare gig comes on the heels of the more-country-than-ever "Tanglewood Numbers," recorded in Nashville and released by Chicago's Drag City label last year.

Sunday

1 p.m., Tapes 'N Tapes: The Minneapolis buzz band share a similar story with Clap Your Hands Say Yeah, having launched a career by spreading their music on the Internet, while drawing from similarly angular and minimalist New Wave sounds on the XL debut, "The Loon."

1:30 p.m., Danielson: After first making his mark as leader of the unbearably shticky, intentionally primitivist combo the Danielson Famile, suburban New Jersey songwriter and producer Bill Danielson branched out with slightly more ambitious though not necessarily more enjoyable sounds on the recent "Ships," which features guests Deerhoof, Sufjan Stevens and Serena-Maneesh. No word on who will join him here.

2 p.m., Jens Lekman: A Swedish pop musician in the tradition of charming eccentrics Jonathan Richman and Stephen Merritt, Lekman's live performances have ranged from a solo act with a guitar and a CD player to much more grandiose presentations featuring a choir and a string quartet. It will be interesting to see what he does in the festival setting.

2:35 p.m.: The National: This Brooklyn-by-way-of-Cincinnati quintet revels in dark explorations of the seamier side of life, as evidenced by its third album, 2005's "Alligator."

3:30 p.m., Liars: Mixing electronica and punk, New York's Liars relocated to Berlin to record their last album, "Drum's Not Dead," released earlier this year. A concept effort about two fictional characters named Drum and Mount Heart Attack, the goal was to incorporate a broader range of influences, from Brian Wilson to Radiohead, and it partly succeeds.

4:20 p.m., Aesop Rock & Mr. Lif: The only mainstage hip-hop act at the festival, Bizarro World rapper Aesop Rock (a k a Ian Matthias Bavitz) is teaming up for this performance with his Definitive Jux labelmate, Perceptionists veteran Mr. Lif (Jeffrey Haynes), one of the most progressive voices on the scene.

5:10 p.m., Mission of Burma: Infamous in its original incarnation as the loudest band anyone had ever heard, the legendary Boston trio Mission of Burma remains an unbelievably potent live act, as well as the rare example of a group of reunited rock heroes whose second go-round is proving to be every bit as inspired as its first. The recent album "The Obliterati" stands tall beside classics such as "Signals, Calls & Marches" (1980) and "Vs." (1983); in concert, listen for the tape-loop contributions of Chicagoan Bob Weston, who'll be manning the soundboard and playing behind-the-scenes Brian Eno.

6:10 p.m., Devendra Banhart: Part stoner-hippie and part much-hyped hipster, Banhart has been hailed as leader of the "freak folk" movement that also includes Faun Fables and Animal Collective. Recordings such as "Rejoicing in the Hands" (2004) and last year's "Cripple Crow" have earned comparisons to visionaries such as Tim Buckley and Nick Drake. I don't buy it, but I've never heard him live, and I'm eager to see whether or not the hype is justified.

7:10 p.m.: Yo La Tengo: I'm proud to say I saw the very first gig by the venerated Hoboken, N.J., indie-rock heroes way back in 1984, when I was barely two years out of high school, and they've rarely disappointed me through three or four dozen shows I've seen since. They're gearing up for the September release of their 12th studio album, the curiously titled "I Am Not Afraid of You and I Will Beat Your Ass," which adds yet another twist to the mix via a horn quartet and strings scored by former Bob Dylan collaborator David Mansfield.

8:10 p.m., Spoon: The Austin art-punks' last album, 2005's "Gimme Fiction," didn't quite match the brilliance of 2002's "Kill the Moonlight," and the group can be hit or miss live, but when the band is on, it's really on. The group has just reissued the earlier, out-of-print EPs, "Telephono" and "Soft Effects."

9:10 p.m., Os Mutantes: The major coup of Pitchfork's bookings is the first Chicago performance and one of the first U.S. shows ever by Os Mutantes, veterans of Brazil's wildly inventive Tropicalia movement in the late '60s and early '70s. Fans of the band's vintage recordings, which have been championed by the likes of David Byrne and Beck, may be disappointed that original singer Rita Lee skipped this reunion. But co-founders and brothers Arnaldo Baptista and Sergio Dias are here, and with luck, they'll keep to the wild simplicity of their earlier material while avoiding the progressive-rock showboating of their later albums. Either way, this will be a historic performance akin to Roky Erickson's appearance at Intonation.