MaGnuX MP3 Control Server is a server that allows you to control the playing of MP3 songs. It uses mpg123 to play the songs, and features playlist management, a builtin Web server, IP-based access control, and much more. It's written entirely in Ruby, which makes it extremely flexible and very easy to extended.
SnackAmp is a multi-platform audio file and streaming music (MP3,Ogg, wav, etc.) player and file organizer suitable for very large music collections. Stand alone executables for Windows or Linux are available for download. An integrated Web server provides the ability to remote control the client and serve your music collection as streaming audio.
Cjukebox is a curses-based player and manager for audio files and playlists. Its user interface was inspired by the Norton Commander for DOS. It does not rely on a separate database application. Playback is handled by the Musicus tool, which plays all audio formats supported by xmms (wav, Ogg, MP3, Flac, MPC, etc.).
AlsaPlayer-Python is a set of python bindings. It allows you to write custom interfaces for AlsaPlayer using the full power of the Python language. This may be three lines of code or a large and complex interface. Also provided is a Python module to control AlsaPlayer from external programs.
Freevo is a Linux application that turns a PC with a TV capture card and/or TV-out into a standalone multimedia jukebox/VCR/PVR/HTPC/DVR/set-top box. It uses MPlayer and other applications to play and record audio and video. It is optimized for use with a TV and remote, but can be used with a monitor and keyboard.