skiTunes is a fast, extensible alternative to iTunes. It can use Apple Quicktime, VLC, MPlayer, LAME, and cdrecord. It differs from Apple's offering in that it is written in Cocoa and uses native widgets, as well as supporting formats iTunes doesn't, such as OGG and WMA. Using native widgets will allow it to automatically match the rest of the OS when a theme is applied, unlike iTunes, which requires hacking in order to make it match. It will also offer a skinnable "mini- mode".
Podget is a simple podcast aggregator optimized for running as a scheduled background job (i.e. cron). It features support for downloading podcasts from RSS and XML feeds, for sorting the podcasts into folders and categories, for importing podcast URLs from iTunes PCAST files and OPML lists, automatic M3U and ASX playlist creation, and automatic cleanup of old podcasts. It also features automatic UTF-16 conversion for podcasts hosted on Windows servers.
Tao is a software package for sound synthesis using physical models. It provides a virtual acoustic material constructed from masses and springs, which can be used as the basis for building quite complex virtual musical instruments. It comes with a synthesis language for creating and playing instruments and a C++ API for those who would like to use it as an object library.
PyKaraoke is a karaoke player which supports the CDG (MP3+G, OGG+G), MIDI (.KAR, .MID), and MPEG formats. The project consists of a GUI frontend and separate pycdg, pykar, and pympg player modules. The GUI provides a full application frontend, with playlist functionality and a searchable database. The pycdg, pykar, and pympg modules can also be used as standalone command-line players or imported into any Python programs that would like CDG, MIDI/KAR, or MPEG playback.