With the festival he helped organize now in its 12th year, Lollapalooza founder Perry Farrell talked to Rolling Stone about his favorite Lolla moments backstage at the fest. “There’s a zillion of them. Watching Eddie Vedder jump from a stack a story high into the crowd back in 1994,” the onetime Jane’s Addiction leader said, even though he meant 1992. “I’ve seen people having sex backstage. That was pretty exciting. I’ve participated myself.” With this year’s Lollapalooza maybe sporting its most power-packed, headliner-heavy lineup yet, what was Farrell looking forward to the most? “I don’t think there will be anything but mayhem when Rage Against the Machine takes the stage,” Farrell said. Turns out he was right. For more of Farrell from Lollapalooza, plus video interviews with the Black Keys, Gogol Bordello and Mason Jennings, check out our Rock ‘N’ Roll Diary from the Chicago fest.

For more behind the scenes photos from backstage at Grant Park, click here.

For our full gallery of live shots from the fest, click here.

[Photo: Josh Rothstein for RollingStone.com]