I've made some software to help me (and others) make music, principally
with MaxMSP and Ableton Live . Some of it is available here.
Some is free, some costs a small amount.
Max For Live device that adds the ability to store and recall ‘snapshots’ of Ableton Live devices in realtime
Max For Live utility device that displays Live API information for the currently selected element of the Ableton Live interface
Max For Live utility device that adds extra functionality to note editing in Ableton Live's MIDI clips
In-depth control of Ableton Live using the Korg Microkontrol (greatly improved on that offered natively)
Cross-platform (Win/OS X) tool for transmitting MIDI from one computer to another via a network (sans hardware MIDI interfaces)
Patch editor/management tool for the Akai Miniak (and Alesis Micron ) synthesiser
Totally meta, see the source code for generating this site!