RPG is a utility that generates random tracks for Renoise, based on a user defined set of parameters.
In fact, RPG generates "Phrases" - a phrase, is a 16 row sequence. By default, RPG will generate 4 consecutive phrases, which sum up to a 64 row track.
RPG is capable of working inside Renoise - while it is running, you may press a HotKey to generate new tracks and paste them directly into Renoise, so it is quite easy to listen to many variations without leaving Renoise at all.