How about chords? Melodies which are paths? Passwords? Lots of great potential here!

Password is 3rd movement of Moonlight Sonata without "typos".

nice... ;-)

Funny how we don't hear that movement much...

Goonies scene where they have to play a sequence correct to avoid triggering a trap:

https://www.youtube.com/watch?v=pUO7Ip0Xc10