It must be August, it must be hot, and it must be time once again to head to Chicago’s Grant Park to celebrate Lollapalooza, the annual Midwest superfestival that packs somewhere arounf 100,000 people into the expansive Chicago waterfront to hear some of the world’s biggest acts along with a great many up-and-comers.

This year, the Lollapalooza brand is celebrating 20 years since it first hit America as a roaming daylong event—with bands such as Nine Inch Nails (who played in daylight!), Ice-T’s metal project Body Count, Siouxsee and the Banshees and Janes Addiction introducing the American people to the alternative nation. A gathering of tribes not really seen since the heyday of the ’60s.

We don’t expect to see as many mohawks or Rollin Band sun tattoos at Lollapalooza 2011, but there’s still plenty of great music to discover. Move ahead and check out URB’s 10 Lollapalooza Acts You Can’t Miss. …MORE