my mums a ballet teacher and has a show every few years a the lycium theatre in crewe and she's had a few experiences.
One year she was in the lighting box in the gods and it went all cold and smelt of perfume, she though it was odd but didnt think too much of it. when she came down somebody said "who was that in the box with you" to which my mum replied "nobody i was on my own". staff there say its a common thing as aparently a ballerina threw herself from the gods because she was in love with a monk but they couldnt be together. the theatre was built where there used to be a monastary, the monk has also been spotted roaming under the stage in a cellar like area too!