Tales of the Scottish Play

[PSMKay]

I'm interested in finding out Horror Stories from Macbeth . . either the play or the opera, which is apparently equally as cursed.  Since Shakespare wrote the play, theatre professionals have called the show cursed.  The most recent explanation that I've heard is that the Witch's incantations in Act 1 were real incantations that Shakespeare adapted.

There also appears to be regional cures for saying "MacBeth" in a theatre . . . the most extensive I've heard of is to leave the theatre, turn around three times, spit over your left shoulder, and ask to be let back in.

Any great horror stories of the Scottish Play, or cures for those who dare to speak his name onstage?