I'll toss in my 2 cents worth...

GIMP: Think of it as the free Photoshop.
http://www.gimp.org/

(The GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages.)

Stereograph: - Stereogram generator
http://stereograph.sourceforge.net/

(Stereograph is a stereogram generator. In detail it is a single image stereogram (SIS) generator. That is a program that produces two-dimensional images that seem to be three-dimensional)

Blender: A cross platform suite of tools for 3D creation.
http://www.blender.org/cms/Home.2.0.html

(Blender is the open source software for 3D modeling, animation, rendering, post-production, interactive creation and playback. Available for all major operating systems under the GNU Public License.)

Stopmotion: - Creates stop-motion animations
http://developer.skolelinux.no/info/...tion/index.htm

(Stopmotion is a free application for creating stop-motion animation movies.)

Sweep: A sound editor for sound samples. It operates on various PCM style files such as .wav, .aiff, and .au.
http://www.metadecks.org/software/sweep/index.html

(Sweep is an audio editor and live playback tool for GNU/Linux, BSD and compatible systems. It supports many music and voice formats including WAV, AIFF, Ogg Vorbis, Speex and MP3, with multichannel editing and LADSPA effects plugins.)

Gnucash: Personal and small business money-management software
http://www.gnucash.org/

(GnuCash allows you to track bank accounts, stocks, income and expenses. As quick and intuitive to use as a checkbook register, it is based on professional accounting principles to ensure balanced books and accurate reports.)

Avidemux: A graphical tool to edit video.
http://fixounet.free.fr/avidemux/

('Avidemux' is a graphical tool to edit video. It can open AVI, MPEG, Nuppelvideo and BMPs. Most common codecs are supported (M-JPEG, MPEG, DivX, Xvid, huffyuv, WMA, etc.) thanks to libavcodec. Video can be edited, cut, appended, filtered (resize/crop/denoise), and re-encoded to either AVI (DivX/Xvid) or MPEG 1/2.)

Q DVD-Author: DVD authoring suite
http://qdvdauthor.sourceforge.net/

(A DVD-authoring program that uses command line tools to create the actual video DVD.)