Ftwalk is a high level script programming language, very similar to awk, but greatly extended to include a richer type system, object-oriented features, 300+ built-in functions, extensibility through dynamic libraries, etc., which makes it roughly comparable to languages like Perl. It does file tree searches, and was originally used to implement selective redundant copy backup stores. It can be run interactively as a calculator.
GASP is a generic protocol encoder and decoder. It offers a complete scripting language (based on Tcl) which allows you to construct or analyze any packet of data based on abstract protocol definition. This version includes all the basics networking protocols (IP, ARP, ICMP, TCP, UDP, and DNS), some protocols for archivers (ZIP, GZIP, and TAR), and some multimedia protocols (JPEG, GIF, and PNG).
gitty-gitty, the (general | GNU) template generation tools, are a set of scripts for creating a whole set of sources which may already be compiled and installed using the GNU development tools. Think of gtgt as a program which is able to create an already compilable, very sophisticated "hello world" program, written in C or C++ and constituted by a main program, two internal modules (classes), and one static and one shared library, and this complex "Hello World" is already fully embedded into the GNU autoconf/automake development environment. By using gitty-gitty, you will get a template of sources for the main cases you might meet, and which you can also use as examples for automake, autoconf, etc.
Glt is a library of C++ classes and routines for programming interactive 3D graphics with OpenGL. The aim of Glt is to augment the OpenGL API with convenient mechanisms for manipulating the OpenGL state machine. Glt is a work in progress, and by no means covers the entire OpenGL specification. However, it already includes several useful classes and is designed so that additional classes can be added easily. In addition to Glt, the GlutMaster classes provide C++ wrappers for the GLUT API.
Libgda is a (relatively small) database access library. It provides a wrapper like ODBC but with more features for accessing several database engines, a general data model for use with CSV or XML files, a metadata extractor that retrieves information about database objects in a common way, and a SQL console application (like mysql, psql or sqlite3 consoles).
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.