Recently I've been fascinated by how effective the design of Super Mario Brother's first level is in teaching the player how to play the game without having to tell the player anything. 

Music Credit and Attribution:

Claude Debussy - Etude XI. Pour les arpeges composes

Performer - Kimiko Ishizaka (Piano)

Publisher Info. - Kimiko Ishizaka

License:

Creative Commons Attribution Share Alike 3.0 

Notes - Recorded live in 2008, Bonn, Germany