Videos about MusicWilliam Wieland
The Power of the Pentatonic Scale (3:00) — Bobby McFerrin at the World Science Festival
SOL-TI-RE-FA Dominant 7 Song (2:15) — A great video about the dominant seventh chord and more.
Capt. Broccoli explains triad positions (4:45) — This is my personal favorite music theory lecture by Captain Broccoli. (He "filmed" several.)
Bernstiein, The greatest 5 min. in music education  (5:59) — First investigate overtones, polyphony, tonic/dominant, and diatonic/chromatic. Next, sing Fair Harvard.

Compelling Videos
  Why an "A" is not enough (4:49) or Jack Stamp - Why Music Matters (6:05)
  Not on the Test (2:14)

What is up with Noises? (The Science and Mathematics of Sound, Frequency, and Pitch) (12:49) — Vi Hart has created many entertaining and educational videos. Most are about math, but she is a musician as well.

Maestros, if you please ... ! (7 talks) — TED lectures are amazing. They are approximately 20 minutes each. Two of my favorites include:
  Benjamin Zander: The transformative power of classical music (20:44)
  Itay Talgam: Lead like the great conductors (20:52)

Tod Machover: When cities create music (17:49) — INKtalks were inspired by TED

Donald Duck in MathMagicLand (27:32) — The first 11 minutes of this classic film explore music as well as the golden section, a profound proportion in nature and art—including music.

Sharp as a Tack - Music Engraving: an Art and a Craft (7:43)