Metakit is a small, portable database library using a hybrid relational / hierarchical data model with a column-wise internal storage format. For C++, include a single header file and 125 kb DLL or statically link directly. Ideal for desktops, embedded systems, smartphones, and PDAs. Bindings for Python and Tcl. A very mature, stable code base.
Funpidgin is a modified version of the Pidgin instant messenger application. It was made in response to the controversial auto-resizing textbox that was implemented in Pidgin. Current features of Funpidgin include manual resizing and the ability to turn off persistent window placement. Funpidgin's releases are meant to coincide with Pidgin's releases.
Micropolis is a city simulation game engine based on the original classic SimCity source code. Micropolis is based on the Tcl/Tk version of SimCity. It consists of the micropolis module, which is the engine recast as a C++ class; the cellengine module, which is a cellular automata machine engine; and the tileengine module, which is a Cairo based tile renderer. It is intended to be used with the OLPC's Sugar user interface environment, but layered so the core code is useful in other contexts.
The QConsole class is a custom widget that implements a basic console, written in C++ and relying on Qt. It implements several features and is intended to be inherited from in order to have a "real" console for a specific scripting language, shell, etc. Example implementations for TCL and Python are included.
Berkeley DB XML is a native XML database engine for use within your product. Made available as a C++ library with language bindings for Java, Perl, Python, PHP, and Tcl, it integrates directly into your application (it is not a standalone database server). It provides XQuery access into a database of document containers. XML documents are stored and indexed in their native format using Berkeley DB as the transactional database engine.