GrandOrgue Virtual Pipe Organ Music Simulator
GrandOrgue is a free and open source sample based pipe organ simulator for Linux, Windows and MacOS. You can connect it to MIDI keyboards and an audio system and GrandOrgue can simulate the sound of a real pipe organ in you system. It supports HW1 compatible file format and you can play sample sets. It is released under open source GNU General Public License version 2.0.