XParam is an extensible, type-safe, non-intrusive, object-oriented tool for general-purpose object serialization and deserialization in C++, good for parsing command-line parameters and cross-program/cross-platform communication. It can handle named parameters as well as object streams. It recognizes class hierarchies, abstract interfaces, and polymorphism, and can therefore serve as a plug-in management framework (e.g., for strategy management).
fnkdat is a C header and source file that may be statically linked to a binary. It provides a platform independent interface for determining common directory names (e.g. "user directory", "config directory", etc...). It's particularly well suited for games, but by no means limited to that use.
lfwmail is a lightweight webmail program. It will run with acceptable speed even on a Pentium 100Mhz Linux mailserver. It has just basic features and no calendar or folders, but it is fully MIME capable and can handle attachments. It is also very secure when you use https encryption. It converts HTML messages to ASCII for security reasons, but you can still see the HTML versions if you want. The code is clean and structured. The installation is straightforward and doesn't require a lot of non-standard modules.