The Cloud Harp. The transposition of a natural phenomenon into music. The melodies and sounds are determined by factors such as cloud height, density, structure, luminosity, and meteorological conditions.
Tunes create context like language : "musical notes are strung together in the same patterns as words in a piece of literature". Full paper. On a related note, hone your musical comprehension by playing with Impromptu. Better yet, co-ordinate it with this MIT OpenCourse - Developing Musical Structures.
Know a tune, but can't identify it? Melodyhound should help. Whistle the tune, record it, and their database can help match it. Can't whistle? No problem. Figure out the Parsons Code directly for the melody, and it will match that.