Wanna See A Show? Two Years Ago?

Okay so we were cleaning up pretty strenuously the other day and found this in the sofa cushions: It's a ticket for a play that was performed more than two years ago. On the day after my spouse's birthday. It was clearly never used. Nobody here remembers buying the ticket or intending to see the play. But there it was, some 30 months later, in our sofa. I sense a mystery novel coming on...