The finite element method (FEM) package SyFi is a C++ library built on top of the symbolic math library GiNaC. The name SyFi stands for Symbolic Finite Elements. The package provides polygonal domains, polynomial spaces, and degrees of freedom as symbolic expressions that are easily manipulated. This makes it easy to define finite elements and variational forms. These elements and forms are then used to generate efficient C++ code....

The i9 project aims to build a reasonably secure, microkernel-based operating system, with binary compatibility to other OSes, a range of Personalities (environments that behave like other OSes). and a comprehensive set of APIs that give users and developers freedom of choice....

LINGOT is a musical instrument tuner. It's accurate, easy to use, and highly configurable. Originally conceived to tune electric guitars, it can now be used to tune other instruments.
It looks like an analogue tuner, with a gauge indicating the relative shift to a certain note, found automatically as the closest note to the estimated frequency....

rlvm is an open source implementation of the RealLive virtual machine for Linux and OSX. RealLive is a game engine used in Japan to write visual novels, a few of which I care about, and many that I do not.

Currently, rlvm works with: Kanon Standard Edition, Air Standard Edition, CLANNAD, CLANNAD Full Voice Edition and Planetarian, along with a few non-KEY games. rlvm can optionally use English patches to some games....

An in-car assistant built with Qt Embedded Linux.,

ENIGMA is a free game and application development toolkit, utilizing GCC and a series of parsers to convert a high level, script-like language based on Game Maker's GML, into C++. The toolkit employs a mixture of both C++ and GML, accepting either.

chemkit is an open source software library for chemistry applications, particularly in the areas of cheminformatics, molecular visualization and molecular modeling.

A C++ GPU Computing Library for OpenCL,

Lcoveralls is a simple (Ruby) script for reporting code coverage results from LCOV to Coveralls.

OSlash is a c++ framework for developing cross-platform applications. It is an Abstraction Layer for the OS services (filesystem, concurrency, timing, memory management) and also a set of efficient data structures (collections, maps and strings).