Librep is a shared library implementing a Lisp dialect that is lightweight, reasonably fast, and highly extensible. It contains an interpreter, byte-code compiler, and virtual machine. Applications may use the interpreter as an extension language, or it may be used for standalone scripts. Rep was originally inspired by Emacs Lisp. However one of the main deficiencies of elisp--the reliance on dynamic scope--has been removed. Also, rep only has a single namespace for symbols.
Jess is a fast, light rule engine and scripting environment written entirely in Java. You can build Java software that has the capacity to "reason" using knowledge you supply in the form of declarative rules. It is supplied as a programmer's library, making it ideal for embedding in larger applications. Jess includes development tools built on the Eclipse platform. It is free for academic use and can be licensed for commercial use.
Invenio (formerly CDSware) is a suite of applications that provides the framework and tools for building and managing an autonomous digital library server. It complies with the Open Archives Initiative metadata harvesting protocol (OAI-PMH) and uses MARC 21 as its underlying bibliographic standard. Its flexibility and performance make it a comprehensive solution for the management of document repositories of moderate to large size.
InteLib is a library of C++ classes that lets you do Lisp/Scheme programming within your C++ programs, even without any additional preprocessing, without all those calling conventions. You can write code that is accepted by a C++ compiler while thinking in a "Lisp/Scheme mode", and the code you write will look much like Lisp/Scheme code, although it will be pure C++.
sawfish.wm.ext.pager is a C/Lisp extension that provides a functional desktop pager for the sawfish window manager. A pager is a map of your desktop. It shows not only the visible part of your desktop (the current viewport), but also the parts that extend beyond the sides of your screen. Also, if you have more than one workspace, the pager will follow you to where you are, or optionally show all workspaces at once. Of course you can select viewports and windows, and also move or raise/lower the latter.