BRL-CAD is a powerful constructive solid geometry solid modeling system that includes an interactive geometry editor, ray-tracing support for rendering and geometric analysis, path-tracing for realistic image synthesis, network distributed framebuffer support, and image and signal-processing tools.
FrAid (Fr[actal] Aid) is a programming language that is appropriate for mathematical computations, visualization, batch processing, and more. It features both a standalone application that provides a programming environment for the language and a system for integrating the language with Java. The Java interface allows mathematical equations and formulas to be used with Java code, making it easier to process numerical computations, symbolic computations, imaging, CAD, and more.
Config::Maker takes a file with data in simple hierarchical format (similar to BIND and DHCP configuration files) and several templates, and produces the text by filling in the values. It is mainly useful for creating related configuration files. It can be used to generate firewall configuration scripts, DNS zone files, DHCP configuration files, a reference from a single file with all users and machines, etc. It's useful when you are not satisfied with keeping information synchronized in several places, but don't want something as complex as cfengine. Snippets of Perl can be used if all else fails.