➟ WolframTones

WolframTones: A remarkable new project from Wolfram Research Labs (makers of Mathematica and Wolfram Alpha) that intelligently generates semi-random music – I believe the term is procedural generation. It makes musically-sound structures, not just random notes, that fit very well into a range of genres selectable by the user.
Bonus points for using retro 8-bit instrument sounds and letting you export the music as files you can use for ringtones or just about anything else. I’m listening to some surprisingly good jazz bits right now.