Music score editor
Canorus is a free cross-platform music score editor. It supports an unlimited number and length of staffs, polyphony, a MIDI playback of notes, chord markings, lyrics, import/export filters to formats like MIDI, MusicXML, ABC Music, MusiXTeX and LilyPond
A cross platform audio inteface
CIOS Audio Core is the infrastructure and subsystem in Collective Intelligence Operation System. It is a cross platforms audio abstract interface, supports including Mac OS X, Linux, Android, iPhone OS and Windows 7.
Sansibar is designed to organize huge MP3 collections with focus on using ID3 tags for building up a database-indexed web-based management interface. If ID3 tags are missing or incomplete, Sansibar will try to lookup the data automatically.
Tinara is a media production system, currently composed of a basic revision control and archival system (DaMarcus), a build system (Alice), an audio playback engine (Tape), and a graphical audio recording and editing application.
A fast and simple GUI for dvdbackup using Ruby-GNOME2. It requires the Ruby-GNOME2 Package, which is available for nearly every OS/Linux distribution. For installation instructions have a look at the README or the Homepage.