I think many creative people like painters or writers would like to have a tool like MIDI Madness for thei profession. But only musicians and producers get the fun. :-) MIDI Madness is easy to understand and after you've got the hang of it you are able to use it to create basslines, melodies, chords and even drum patterns.
Make 4 Tracks, drums, bass, pad and lead, load an instance of MIDI Madness for each track, tweak, use the random features and in the end you will get for example a nice ambient sounding endless song...without recording or setting a single note in the piano-roll. :-).
In the 2.1 update, the AU MIDI FX format is added and it works like a charm in Logic X. No more hassle in the environment page, just load it into the MIDI fx slot and there you go. A great tool to create inspiring CC automation on your generated sequences. The plugin was launched Q1 2014 and already some major additions have been added to give the plugin more potential. The developer listens to the feedback of his buyers, which I appreciate a lot. Steep price, but great value for your money.