Mine was one of three possible shows I saw around 9th or 10th grade, but the order has grown fuzzy over the years. It was either Alice Cooper outdoors at the old Victory Field/Bush Stadium on 16th Street (Indy), Mountain (Felix Cavallari and Leslie Winter) at Sherwood Country Club, which I think was near Beech Grove on Indy's SE side, or Black Sabbath at the Indiana Theatre in downtown Indy...
Actually I attended the Sabbath show, but they decided not to. The Indiana was a cinema where they showed epic movies like Lawrence of Arabia, Caesar and Cleopatra, Sound of Music etc... The theatre sold orange juice in plastic orange shaped containers, which I later saw in Broadway theatres as well. So people were likely mixing booze in with their orange juice and these suckers were hard plastic...
Anyway after an hour or so when it became obvious Sabbath was a no-show it was a rowdy crowd. I remember the theatre either brought in a local band, or maybe it was the opening act on the bill, but eventually they announced that Sabbath wasn't going to perform. It turned into a near riot, and I'll never forget the sight of all those plastic orange juice containers being hurled at the poor guys who were trying to perform...
Just did a google and it turns out the show in 1971 was cancelled due to sound system issues. Never knew that, or the fact that the show was rescheduled or that Irving Azov was the promoter. It was the Paranoid tour, and all I really remember are all those plastic oranges raining down on the stage...
Clipping found in The Indianapolis Star published in Indianapolis, Indiana on 8/19/1971. Black Sabbath Indianapolis cancellation
www.newspapers.com