[gekkostate]

One option is Wolfram Tones (tones.wolfram.com/generate). It uses cellular automatons (so not quite AI but achieves your goal) to generate music.

- You can change the type of music (Jazz, Classic etc.), select instruments and so on

- You can download the music as well

The only downside is that you can only get a maximum of 30 seconds. What you can do however, is go to their free programming lab and write some code to generate any length that you might want.