Guvcview provides a simple GTK interface for capturing and viewing video from devices supported by the Linux UVC driver, although it should also work with any video4Linux2-compatible device.
Calise grabs frames from a camera, returns "correct" screen backlight steps associated with them, and sets those values. It can be run with or without the Xorg environment, and on X comes with a pretty (optional) GUI.
A frontend for ClamAV.
A programming language with the ease of a scripting language and the performance of a compiled language.