Paranormal is an extremely customizable visualization plugin for XMMS, based (conceptually) on Winamp's AVS plugin. Its goal is to be as flexible as possible by providing a number of 'actuators' that perform various tasks involved in generating an image. These actuators can then be combined to create a nearly unlimited number of effects.
libclfll++ takes advantage of the abstract Library Load framework in the CoreLinux libclfw++ library by providing management of loading Linux shared libraries. Application developers define function objects as wrappers and can then dynamically load the functions. It is very useful for implementing a framework for plug-ins.
The deimos project provides some platform independent libraries which contain a reference memory allocator (garbage collector planned), virtual filesystem (Unix sockets, HTTP, etc), configfile management, and a clean build system (easy makefiles). These libs are used by DDS (Digital Disco System - mp3 player), vmOberon (oberon virtual machine), and ODMS (open document management system).