Flexible open-source content management and blogging software with an active user and developer community and a wide variety of plug-ins or extensions available.
Full-featured open source office productivity suite, featuring word processor, spreadsheet, presentation, drawing and database packages; free MS Office replacement.
Inkscape is an Open Source vector graphics editor, with capabilities similar to Illustrator, Freehand, CorelDraw, or Xara X using the W3C standard Scalable Vector Graphics (SVG) file format.
VLC media player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs, VCDs, and various streaming protocols.
The Social Source Commons is a “knowledge commons” that provides users with: a directory of software applications; links to relevant documentation, localization tools, services, user reviews; and a place to request tools/features.