TrebleMaker - Procedurally generated, royalty-free MIDI compositions
WolframTones - Listen to what I just found in the WolframTones music universe
Abundant Music - Generate royalty free music with a simple but very powerful procedural music creator
Odesi - ODESI is a music sketchpad that exports your projects to Audio and MIDI.
WaveBots Editor - Procedural music and sound maker that exports to Wav, MIDI, GoatTracker and much more.
Automated Composing System - ACS creates automated arrangements so you can compose music without musical knowledge.