Macfork can be used to both list and extract resources from a Macintosh resource fork under unix. Currently it supports icon families, pict resources and palettes, but the data from any resource may be extracted to a data file. It was written to port Macintosh icons and pictures over to unix, but has many other potential uses.
Radiator is a radiosity renderer. It implements matrix, progressive, and hierarchical radiosity with clustering, and handles a variety of model formats, including multiresolution models. It also comes with a visualisation front-end, 'radvis', useful for previewing scenes or teaching, a scene viewer 'slview', and a Mesa-based batch rendering program, 'slrender'.
SunSky uses the Utah sun/sky model to draw plots of the entire sky, or a specific window of the sky, for a given location, time, and view direction. You can also vary the turbidity, which controls the level of haze in the atmosphere. (Los Angeles would have an extremely high turbidity, Greenland would have an extremely low one.) A little tweaking can quickly lead to a picture of the glorious sunset you'd be seeing outside if it wasn't currently pouring with rain. SunSky can also draw the CIE colour diagram, and various spectra, including blackbody radiation and the CIE basis functions.