There have been plenty of impressively elaborate musical machines in recent years, but this might top them all. Swedish band Wintergatan has crafted a Musical Marble Machine that, as the name suggests, churns out tunes using 2,000 marbles (technically, ball bearings). It's a pretty involved effort with 3,000 parts that include a crank, levers, conveyor belts and legions of spinning gears -- Rube Goldberg would be proud, especially if he knew that this beast took 14 months to make.
The results speak for themselves. One person can play bass guitar, vibraphone and drums... and importantly, play them well. There's even a "breakdown" lever for that all-important bridge section. You're unlikely to see the Musical Marble Machine in concert (moving it anywhere is a supreme challenge), but it serves as testament to what engineering can do when it's put to work by musicians.