If you were boning up on hot halloween costumes The Andy Warhol Museum was the place to be Saturday night. More than 250 came for the Arthritis Foundation's annual Bone Bash, Witches, Warlocks and Warhol benefit. The two-tiered event began with cocktails, dinner and a silent auction and ended with a flood of new blood arriving at 9 p.m. for the Factory Dance Party and costume contest. Looking like a member of the band Kiss, John Innocenti, president of UPMC Presbyterian Shadyside Hospital, was honored along with John Banaszak, assistant head coach of Robert Morris University football. He came in suit and tie -- perhaps he was a banker. Event chairs Dr. Larry and Diane Crossett got into the spirit of the evening as Andy Warhol and a Jazz Age flapper.