PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
DIIT provides a simple tool that can hide a message inside a 24-bit colour image so that knowing how it was embedded, or performing statistical analysis, does not make it any easier to find the concealed information. It also provides a framework for implementing other steganography algorithms for use in the tool.
Visprint makes cool fractal fingerprint PNG images based on the contents of any file. The image will be different for almost every file with even slightly different contents. Visprint uses the IFS fractal generation process pioneered by Michael Barnsley. It is a way to create images that are self-similar to infinite depths. In other words, the picture is made up of smaller versions of itself. Visprint takes a hash function checksum as its input.