[ericathegreat]

Would definitely recommend the mini-series documentary "Howard Goodall's Big Bangs".

Episode 3 in particular, which was about equal temperament, is especially good. It explains things like scales and chords in a very satisfying way for both experienced musicians and those who have not had a formal education. He even ties it back to the actual physics of sound and harmonics.

It's only got half a dozen episodes, so it's worth a go.