drizzle-php-ext is a PHP front end for the Drizzle client and protocol library (libdrizzle). It aims to provide a simple interface closely tied to the C library by minimizing interface changes, avoiding duplicate code, and not introducing any new functionality that is not PHP specific.
GNU dico is a flexible dictionary server with a set of accompanying utilities. It supports a wide variety of dictionary database formats, ranging from the traditional "dict.org" databases up to Wikipedia format. Support for arbitrary new formats can be easily added using loadable modules. The dico library provides an API for writing new modules in C, Guile, or Python.
swampex (or Swamp Explorer) is a cross-platform library designed to work with raster maps in Ozi Explorer format. Using this library, you'll be able to collect maps in the file system, get information about map calibration, find maps by latitude/longitude, render maps in SDL surfaces, and more.