ColPy is a small Python library for conversion and computation of colors. It supports conversion to and from 22 color spaces, and 20 CIE standard illuminants.
Kolourmatica is a simple color space calculator that allows conversions between 22 different color spaces. It also renders each color space in every other system color space.
Voidoria is Fractal Flame rendering and animation software.
A full-featured outliner for Vim.
A GTK-based xmessage clone.