A nice comment came at the end of the Long Now discussion between Brian Emo (composer) and Will Wright (game designer):
It’s interesting that just one verb is used both for music and for games: “play.”
This seems to be true in a large number of languages too, which implies some kind of universality of the concept. I also note that my dictionary says the English word play is related to the Middle Dutch word pleien: ‘leap for joy; dance’.
(The discussion, by the way, was excellent. You can download audio in OGG or MP3 or read Stewart Brand’s summary.)