An extremely powerful and configurable BitTorrent client
Vuze (formerly Azureus) is an extremely powerful and configurable BitTorrent client. Search and download torrent files. Play, convert and transcode videos and music for playing on many devices such as PSP, TiVo, XBox, PS3, iTunes (iPhone, iPod, Apple TV).
Streams many media formats with minimal configuration
Universal Media Server is a DLNA-compliant UPnP Media Server Universal Media Server supports all major operating systems, with versions for Windows, Linux and Mac OS X. The program streams or transcodes many different media formats with little or no configuration. UMS is powered by MEncoder, FFmpeg, tsMuxeR, AviSynth, MediaInfo and more, which combine to offer support for a wide range of media formats Check out the list of media renderers here: http://www.universalmediaserver.com/about/
Cross-platform player and audio manager
aTunes is a powerful, full-featured, cross-platform player and manager, with support for online radios, podcasts and CD ripping.
The future of information technology will be based on controlling the flow of natural light. This project is an attempt to establish the code (or software) that will enable this to happen. It involves rewriting an OS from the ground up.
GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching geometry, algebra, statistics, and calculus. Download the free software at http://www.geogebra.org. Find the source code at http://www.geogebra.org/trac