GTKMathplot is an interactive plotting program based on GTK+ and the Cairo graphics library. It can display bidimensional curves, tridimensional curves, and surfaces from Cartesian or parametric equations describing the mathematical objects you would like to visualize. It is designed to be intuitive for high school students with good mathematical knowledge. University students of engineering, physics, mathematics, or natural sciences should need no explanation at all to start using it proficiently.
Booleano is an interpreter of Boolean expressions; a library to define and run filters available as text (e.g. in a natural language) or in Python code. In order to handle text-based filters, Booleano ships with a fully-featured parser whose grammar is adaptive: Its properties can be overridden using simple configuration directives. On the other hand, the library exposes a Pythonic API for filters written in pure Python. These filters are particularly useful to build reusable conditions from objects provided by a third party library.
A lot of stereoscopic cameras use the .MPO format to store two JPEG images, including the Fuji W1, W3, and a few 3D camcorders that have a still mode. It can do two things for you: it can separate out the image files into a left and right pair, so you can process them or do whatever you want with them, or it can create an anaglyphic image (the ones you need coloured glasses to view). It is simple to use from the command line and takes wildcards, so you could process a whole batch of files with: mungempo *.MPO.
Brutal squirrel is a converter to hex digits (plain text) and back. Using it, you can use your favorite text editor (such as vi or emacs) as a hex editor. You can compose any binary file or text file with non-keyboard symbols directly as hex digits. It reads from standard input and outputs to standard output.