This has probably been covered before but as it's Halloween and in the interests of provoking conversation:)

Mine is our production of Rumors which just ended.

We opened on a Thursday. After Tuesday night's rehearsal one of the actors had a heart attack and we had no understudy (it was hard enough finding enough men to cast the show.) Another actor was called in with the plan being that he would play the part holding the book. He did that for the dress rehearsal to which media had been invited to preview the show. With the obvious complicated blocking and rapid fire dialogue it was the roughest dress rehearsal I've ever been involved in.

Then at strike a door frame fell and hit one of the actresses in the head. She had to be taken out on a stretcher by the rescue squad and taken to the hospital.

The good part: She was OK. And the actor who had the heart attack most amazingly came back starting opening night and finished the show. The show must go on!

No major horrors in my history. Just the occasional missed cue.

I was in "Star Spangled Girl" once, playing Andy. The show starts with Andy entering his apartment, listening to the answering machine, looking through the mail, and then the phone rings and away we go with the play. Opening night (you could see this coming, right?) the phone didn't ring. Someone had pulled the cord. It was probably only a twenty second delay, but it was an eternity there on stage.

Another time I was in "A Walk In The Woods" - a two character play. In the middle of one of my many monologues, I got lost - couldn't remember what came next. I turned to my fellow cast member after a long pause and said, "Let me see, where was I?" - figuring he could help get me back on track. I'll never forget his response; a rueful smile, a shake of the head, and he very sincerely said, "I have no idea."

But, no sets falling down, no audiences walking out en masse, no falling chandeliers - Lucky me (so far).