By | August 03 2012 3:39 PM

The twenty-first year of the Lollapalooza festival gets underway on Friday with performances from perhaps the most anticipated set of the evening, a reunited Black Sabbath. Tickets for the music festival sold out months ago but are in such high demand that they're currently being sold on secondary markets with the cheapest 3-day pass costing almost $400. For fans that can't make it to Chicago's Grant Park for the festivities many performances will be available for streaming on Lollapalooza's YouTube channel.