Upon a Fold, the most excellent paper blog, I found the story of a strange piece of music composed by Erik Satie called "Vexations" that was, according to the composer, to be played 840 times in succession. The piece was never performed during his lifetime, but 56 years later, when it was finally published, a few piano masochists apparently gave it a shot.
Fast forward to the present...Composer, Martin Arnold has the bright idea to orchestrate the piece for two pianos and have it performed at an all-night contemporary art event. The piece is 90 seconds long and took the two pianists, playing simultaneously, approximately 12 hours make it through the piece 420 times each. While this madness was going on, artist, Micah Lexier was busy keeping track of how many times the piece had been played by folding 840 copies of the score into origami shapes.
Sometimes it amazes me that things like this exist, and that they probably started with the simple phrase..."Hey. I've got an idea..."
Whole story here.