Jmol is a Free, Open Source molecule viewer and editor. It is a collaboratively developed visualization and measurement tool for chemical scientists. Jmol is an active project, and there are new features being added to it on a daily basis. Users are encouraged to modify it to fit their needs and to contribute their changes to the project.
QCad is a powerful but easy to use 2D CAD program for Linux, Windows, and Mac OS X. It uses DXF as its standard file format. While other CAD packages are often rather complicated to use, QCad tries to stay comfortable, and even an absolute beginner can create professional drawings with a minimum of effort.
There are many photo-gallery programs available. Zoph is different, as it concentrates on the management of large collection of photos instead of just showing them on the Web. It can store a lot of information about your photos, including the regular EXIF info, photographer, location, title, description, rating, and the people in the photo. Photos can appear in multiple albums and categories. Additional features include search, slideshows, lightboxes, email, access privileges, and multiple languages.
Tux Paint is a simple and entertaining drawing program geared towards young children. It has a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin). Along with drawing brush strokes, lines and shapes, you can also enter text and place "rubber stamp" (or "sticker") images on the picture. Tux Paint is extensible, and could be useful in an educational environment (such as a grammar, elementary, or grade school). It's portable across numerous platforms, and runs well even on slower systems like the Pentium 133MHz.
Zina is a graphical interface to your MP3 collection, a personal jukebox, a Podcaster, and an MP3 streamer. It includes an optional Flash player, a tag editor, and can search the Web for album art and song lyrics. It can run alone, be embedded into an existing Web site, or be used as a module in Drupal, Joomla, and Wordpress.
ZoneMinder is a suite of applications intended for use in video camera security applications, including theft prevention and child or family member monitoring. It supports capture, analysis, recording, and monitoring of video data coming from one or more video or network cameras attached to a Linux system. It also features a user-friendly Web interface which allows viewing, archival, review, and deletion of images and movies captured by the cameras. The image analysis system is highly configurable, permitting retention of specific events, while eliminating false positives. ZoneMinder supports both directly connected and network cameras and is built around the definition of a set of individual 'zones' of varying sensitivity and functionality for each camera. This allows the elimination of regions which should be ignored or the definition of areas which will alarm if various thresholds are exceeded in conjunction with other zones. All management, control, and other functions are supported through the Web interface.
LiVES is a simple to use yet powerful video effects, editing, conversion, and playback system aimed at the digital video artist and VJ. It runs under Linux, BSD, Mac OS X/Darwin, IRIX, and openMosix. It is frame and sample accurate, can handle almost all types of video, and is fully extendable through plugins and the included plugin builder tool. It can also be controlled remotely using OSC.
mod_musicindex is an Apache module aimed at being a C alternative to the Perl module Apache::MP3. It allows nice displaying of directories containing MP3, Ogg Vorbis, FLAC, or MP4/AAC files, including sorting them on various fields, streaming/downloading them, constructing playlists, and searching. It also provides features such as RSS and Podcast feeds, multiple CSS support, and archive downloads.