Lollapalooza kicked off today (Aug. 1) in Chicago's Grant Park, with acts like the Raconteurs, Cat Power, Stephen Malkmus & the Jicks, Bloc Party, CSS and the Cool Kids setting the table for a sla

Lollapalooza kicked off today (Aug. 1) in Chicago's Grant Park, with acts like the Raconteurs, Cat Power, Stephen Malkmus & the Jicks, Bloc Party, CSS and the Cool Kids setting the table for a slavishly anticipated headlining set from Radiohead.

The latter band's performance will go heavy on material from its acclaimed 2007 album, "In Rainbows," along with a handful of choice nuggets from 1995's "The Bends." This is Radiohead's first North American show on the second leg of its summer tour.

Also, for the first time since its reinvention as a destination festival in 2005, a single day of Lollapalooza sold out at 75,000 tickets. Tickets remain for tomorrow and Sunday.

The day began with a literal bang in the form of Bang Camaro, who kick-started Lollapalooza with an 11:30 a.m. set. Festivalgoers endured a windless 90-degree-plus day on the edge of Lake Michigan, but rocked out early to bands like Rogue Wave and Noah & the Whale, both of whom performed on two different stages.

Hip-hop groups like Cadence Weapon and Free Sol also had a place, while Gogol Bordello offered its trademark showmanship in a sweat-drenched set featuring backup dancers decked out in lime-green tribal wear. The Honeybears and Black Joe Lewis were a funky crowd favorite on the BMI stage, earning favorable comparisons to retro-leaning acts like the Dap-Kings.

With the sun threatening to set, Cat Power's Chan Marshall, decked out in a T-shirt with the slogan "People Make the Peace," soothed the audience at the Playstation-branded stage, while Mates Of Stage fleshed out material from their latest Barsuk album, "Re-Arrange Us," with full band accompaniment.

For full event coverage all weekend, visit Billboard's Lollapalooza microsite.