Portal - Carol Of The Turrets

Makes me feel so inadequate to know there are people who can do this in their spare time.

https://www.youtube.com/watch?v=J0NXY89WsxY

Brilliant.

You may also enjoy Carol of the Belts.

Cute, but they mixed in too much of the melody and not enough of the harmony. The rich harmony is kind of the point of Carol of the Bells.