Swiss army knife of image processing
GraphicsMagick provides a set of commandline tools and programming APIs for manipulating, editing, and converting raster and vector images. It is derived from ImageMagick, with the objective of providing better stability and performance than ImageMagick while retaining the original MIT/X11 license.
Java Slideshow is a platform independent image viewer especially for huge collections. It provides an easy command line interface, supports tagging and view by category, zoom, move and has some file manager functions like delete file or find duplicates.
AstroCam is an C based daemon process for Linux and BSD to control stepmotors via SMC 800 cards. AstroCam also includes both, an PHP-based WebInterface and one based on Perl, for remote Stepengine control. You can control webcams with it.
PENGL is a PENGEOM geometry viewer written in C using OpenGL. PENGEOM is the geometry description routine coming with Penelope (Monte Carlo code for simulation of electron, positron and photon transport).
Teletext4www is a system that allows you to browse teletext pages with your webbrowser. It has big (as big as your disk) page cache and can work with multiple tv channels. It should support all v4l-vbi compatbile tv-cards.