Mikmod is a module player and library supporting many formats, including mod, s3m, it, and xm. Originally a player for MS-DOS, MikMod has been ported to other platforms, such as Unix, Macintosh, BeOS, and Java(!!)
Nosefart plays NSF (NES sound format) files so you can listen to those old tunes without actually having to play the games. It runs in Linux, DOS/Windows, and as a plugin to various players, including Winamp and XMMS. It was mostly written by Matt Co
AdPlug is a cross-platform OPL2 audio player library. AdPlug plays music, originally composed for the AdLib (OPL2) audio board, on top of an OPL2 emulator or by using the real hardware. There are multiple player software interfaces available.
Drum machine compiler, generic music sequencer and mixer: Write or generate drum and tone patterns in a simple programming language. Mix it using the sample assembler (asampler). Renders to files or plays real-time. Very portable. Works on old hardware.
J Sound System aims to become a multi-platform, API portable sound system for Free Pascal programs written in object-oriented Pascal and i386 assembler.
Batch file front end for playing media files with your favorite player (Like mplayer) Designed to allow for a "ten foot" interface and all navigation done with a number pad.
Very good multimedia player for DOS Standard version - works in text mode,supports: OGG,MP3,WAV,MID,MOD,XM,S3M,IT,CD audio and so on... Now avaiable: GUI version! (using CGUI) Now supports WAV MP3 and OGG in nearly proper way ;)
NovaX is a set of programs that is being devloped for small company's and beginners in the fields of HTML and programming. Coded in Python and C++, this is also a good replacement for MS Office. NOTE: This requires Python to be on your PC. ( Python.org )