This is the precursor to mxTune. It is way behind the functionality and features of mxTune for 1.9.4+. I may update it at some point, but it's not a priority.
This mod adds musical instruments that allow you to play music in MML format. This is a format already used in some popular online games so there are many tunes available or you can create your own. You can play solo or in groups of up to eight players.