Would you believe that some of the trains in the New York City subway system happen to play the first three notes of "Somewhere" from West Side Story (or the corresponding passage in the Beethoven Emperor Concerto, where the sequence of notes sat for a long time before Bernstein emancipated them and brought them into the musical theater and into popular culture)? The subway even plays the passage in rhythm, and at a perfectly lovely tempo.
This musical miracle comes as a result of something about the difference between alternating current and direct current, the third rail, and something that happens that excites the steel of the tracks. I don't understand the physics, but you can read all about it and listen to it over at The New York Times. It's awesome.