Drone in D by Kevin MacLeod
A very long piece of highly relaxing music - done as mostly a piano impromptu over a simple drone (very long note). The piece is in the key of D... mostly. (usually, there is an F sharp and C sharp - this uses an F sharp and B flat... there is no name for this that I know of)
You can download the full uncompressed WAV file of this file here. You can get even more bonus content with the Mega Ambient download here!
Wonderful piece, kudos!