The Boston symphony orchestra was playing Beethoven's ninth..
And during said piece there's about 20 minutes where the two bassists (those playing the double bass) have nothing to do.
So, rather than sitting around doing nothing, they decided to sneak out for a drink at the pub next door. After slamming a couple of shots (as bassists are prone to do), one of them looks at his watch and says "crap, we're late!", to which the other bassist responds "don't worry, I tied together the last few pages with string, it'll take the conductor a few minutes to get them untangled".
So the bassists stumble in and take their places as the conductor is untangling the string tying together the last few pages of the music.
This is noted by one the members of the audience, who mentions this to her companion. "But of course," her companion said. "It's the bottom of the ninth, the scores are tied and the bassists are loaded"