The C++ Portable Types Library (PTypes) is a simple alternative to the STL that includes multithreading and networking. It defines dynamic strings, character sets, variants, lists and other basic data types along with threads, synchronization primitives and IP sockets. It is portable across modern Unix and Windows systems and includes a sample HTTP daemon showing the full power of the library.
mksite.sh is a static Web site / project HTML documentation formatter that only requires the Bourne shell and sed. It gives a common look and full navigation to an HTML Web site along with all the needed metadata detection, site map generation, and variable expansion. It has a tabbed layout suitable for hundreds of Web pages, and is small enough to be added to any project tarball.
HappyHTTP is a simple C++ library for issuing HTTP requests and processing responses. It is simple to integrate: just drop in the .h and .cpp files. It has an easy-to-use interface, non-blocking operation (suitable for use in game update loops), and pipelining support (you can issue multiple requests without waiting for responses).
nc-cms is a simple, fast, easy-to-use content management system (CMS). As you may know, these systems are traditionally very large, complex, and can take many weeks to integrate into a Web site. nc-cms can be integrated within an hour. It's great for managing a site with a set amount of pages.