Tonal music with more than twelve tones per octave.
Using Max/MSP, I designed an environment that facilitates composing in tuning systems with any number of equal tones per octave. With this, I composed scores that a pianist could play using a silent MIDI keyboard, re-tuned live via my program. The pieces I've composed so far are parodies of known styles. Please read my essay to learn more about why I would want to write music this way, and for an analysis of one of the compositions.
The dTone Max/MSP patch re-tunes incoming MIDI note messages to create d even tones per octave.