Conseptizer is two things: 1. a closure(-mimic) / higher-order programming and dynamic typing library for the C programming language, 2. a very dynamic programming language that provides expressiveness through simplicity and offers powerful features that cannot be found in mainstream languages today. Each of these two aspects can be useful on their own, but the combination and tight integration in Conseptizer means: if at some point your runtime performance requirements are not fulfilled by the dynamic language, it is very easy to migrate parts of your program code to C.
getxbook is a collection of tools to download books from websites. There are tools to download from Google Books' "book preview", Amazon's "look inside the book", and Barnes and Noble's "book viewer". There is an optional GUI written in Tcl/Tk, and some shell scripts using OCR to create plain text or searchable PDFs and DjVu files from the downloaded books.
s6-dns is a small, efficient, complete, and IPv6-ready DNS client library, with synchronous as well as asynchronous APIs. It is designed to replace libresolv in projects that need to perform DNS resolution. It also comes with small command-line utilities to make common and not so common DNS queries.
Lhasa is a Free Software replacement for the Unix LHA tool, for decompressing .lzh (LHA/LHarc) and .lzs (LArc) archives. The backend for the tool is a library, so it can be reused for other purposes. Lhasa aims to be compatible with as many types of lzh/lzs archives as possible. It also aims to generate the same output as the (non-free) Unix LHA tool, so it will act as a drop-in free replacement.
xmlsd is a library that wraps expat in order to simplify XML use in C programs as well as adding rigid rules to an XML structure. The idea is to have XML structures that can be passed over the network with implicit parameter verification. This in turn enables back and forth chattering between applications.