Real-time MIDI renderer. Sontica is cool if you use it properly. It is a "console" Windows app, so you'll have to use command-line parameters to tell it what to do. Make yourself a new program group called "Sonitica" or something and add items with the following command lines:
sonc genmidi.son -m
sonc defmod.son

The results should be pretty chill. SONITICA.RTF is the documentation, but it's unfinished -- just look at the programs and play around with 'em. You can also use MOD2MIDI to make Sonitica programs from .MOD files.

If you have two or more sound devices in your system, you'll have to change the SONC.INI file to tell the program which ones to use for input & output. And be sure you set the sample & include paths correctly.