King Crimson and Todd Rundgren played a double bill here on April 27, 1973, according to information on the Web. Peter Key, a columnist for the Philadelphia Business Journal online, 5/10/13, wrote that it was on the Friday of Mother's Day weekend of 1973, which would have been Friday, May 11, so his memory must be faulty. But his article did clue me in to what must have been a wonderful concert on the University of Pennsylvania campus.