MakeNG is a system of makefiles that, in conjuncture with a patch to GNU Make, provides a concise, extensible, logically organized and easily modified system of makefiles to build any source tree or combination of components you can envision. MakeNG sports a fully documented extensible API on top of the classic GNU Make syntax (which is great for backwards compatibility).
Xmake is a console application for building C/C++ projects. It uses XML syntax to describe the necessary files required to build a project and is much easier to explain than make. It is based on a project with one or more "configurations", thus allowing a single file to build across multiple platforms/compilers. Each of the specified source files can belong to one or more of the configurations. The program will automatically do dependency checking for consecutive builds. There are pre- and post-build steps that allow you execute commands to the shell. The pre/post-build steps are also linked to the configuration, so you can be platform specific per configuration.
Jaxor is a simple but powerful tool for creating an object to relational mapping layer. It allows developers to painlessly insert, update, and delete rows from tables, but can be expanded on to create an extensible mapping layer that creates a full domain model, transparently mapping to database tables.
LKMB is a Perl module that can be used to create a kernel module package, that can later be used to create a package that can be bootstrapped on any GNU machine. It is incomplete, but still partially usable. LKMB is part of the Comprehensive Linux Archive Network (CLAN) meta-project.
CASM is an offline content management tool. It is ideal for creating and maintaining dynamic or static Web, WAP, or XML sites. CASM is implemented as an integrated command-line application which contains the Content Assembling Language compiler, an optimizer for HTML, CSS, and XML, HTML tidy integration, a powerful site file structure builder, and more. Content Assmebling Language (CAL) is a markup language designed to separate site content from display properties. CAL has a comfortable templating mechanism, if-then-else structure, variable substitution, file including, recordset handling, looping functions, and embedded Perl scripting.