Wintergatan is a swedish folk band that has built a musical instruments playing music with 2000 marbles, this video is incredible I love this track and hope you'll enjoy too :)
They have also shared some videos describing the making process; below you'll find a description of how everything works.
Reminds me of those old CGI music machines from back in the early 2000's
Yes I remember that one it was really popular, Just found this ;) http://www.howtogeek.com/108654/intel-recreates-animusics-pipe-dream-music-machine-in-real-life/