Lollapalooza music festival

A woman enjoys a mud slide at the Lollapalooza music festival at Grant Park in Chicago on Sunday, August 7, 2011.  (AP/Nam Y. Huh)

Music fans watch PerryEtty vs Chris Cox perform during the Lollapalooza music festival at Grant Park in Chicago on Saturday, August 6, 2011.  (AP/Nam Y. Huh)

Sklyer Grey performs during the Lollapalooza music festival at Grant Park in Chicago on Saturday, August 6, 2011. More than 60 performances will close the three-day music bash on Sunday in Chicago's Grant Park.  (AP/Nam Y. Huh)

A music fan cools off during the Lollapalooza music festival at Grant Park in Chicago, Saturday, Aug. 6, 2011. More than 60 performances will close the three-day music bash on Sunday in Chicago's Grant Park. The festival expanded its space this year and offered more than 130 acts to a record 270,000 attendees. (AP Photo/Nam Y. Huh) (AP/Nam Y. Huh)

Sam Rich poses for his friend during the Lollapalooza music festival at Grant Park in Chicago, Saturday, Aug. 6, 2011.  (AP/Nam Y. Huh)

My Morning Jacket's singer Jim James performs during the Lollapalooza music festival at Grant Park in Chicago, Saturday, Aug. 6, 2011. More than 60 performances will close the three-day music bash on Sunday in Chicago's Grant Park.  (AP/Nam Y. Huh)

Music fans wait to watch for Damian Marley and Nas perform in the rain during the Lollapalooza music festival at Grant Park in Chicago on August on 7, 2011. (AP/Nam Y. Huh)

The Cars' Elliot Easton performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011. The festival expanded its space this year and offered more than 130 acts to a record 270,000 attendees.  (AP/Nam Y. Huh)

Music fans attend the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

Cold War Kids lead singer Nathan Willett performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

Mariah Vailahi, of Chicago, watches the Cars perform during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011. More than 60 performances will close the three-day music bash on Sunday in Chicago's Grant Park.  (AP/Nam Y. Huh)

Damian Marley, left, and Nas perform during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

Nas performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011. (AP/Nam Y. Huh)

Cynthia Flowes waits to watch Damian Marley and Nas's performance during the rainy weather at the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

Damian Marley performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

The Cars' Greg Hawkes performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011. The festival expanded its space this year and offered more than 130 acts to a record 270,000 attendees.  (AP/Nam Y. Huh)

The Cars' David Robinson performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

The Cars lead singer Ric Ocasek, right, guitar Elliot Easton perform during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

The Cars lead singer Ric Ocasek performs during the Lollapalooza music festival at Grant Park in Chicago on August 7, 2011.  (AP/Nam Y. Huh)

A music fan takes photos of Sklyer Grey performing during the Lollapalooza music festival at Grant Park in Chicago, Saturday, Aug. 6, 2011. More than 60 performances will close the three-day music bash on Sunday in Chicago's Grant Park. The festival expanded its space this year and offered more than 130 acts to a record 270,000 attendees.  (AP/Nam Y. Huh)