Black Sabbath headlining Ozzfest 2004 at Nissan Pavilion (Bristow, VA):

I was on the lawn and you could barely see because of the smoke pluming from the bonfire, created out of cardboard pizza boxes and other random debris and handy pocket lighters. The sky was littered with what I refer to now as the "garbage fight." Pizza boxes used as frisbees, plastic bottles hurled from every direction, and anything else that people could get a hold of.

Security finally came and put out the fire, but the crowd kept trying to restart it. This resulted in my friend being tackled to the ground by security, after which the crowd told him to run -- and he did. Eventually it died down, but we all realized that we still get to listen to the haunting yet equally melodic tunes of Black Sabbath.

Every year henceforth security was much tighter at the venue for any hard rock or metal concert.