Fun fact: the "Zen music" from Children of Men is a track by Aphex Twin [1] with a Creative Commons-licensed sound effect [2] dubbed over it. This got quite a bit of attention at the time (e.g, [3]), as it was one of the first documented instances of a major film using CC assets.

[1]: https://www.youtube.com/watch?v=ltLOrgnfW9w

[2]: https://www.freesound.org/people/thanvannispen/sounds/9432/

[3]: https://creativecommons.org/2007/01/17/freesound-sample-in-c...