These are the free, open source projects that I'm currently developing or that I've been developing within the last few years. They are all written in C++ using the Qt framework and released under GPL license.
For more information please refer to the dedicated website of each of those projects.
WebIssues is an open source, multi-platform system for issue tracking and team collaboration. It can be used to store, share and track issues with various attributes, comments and file attachments. It is easy to install and use but has many capabilities and is highly customizable.
Saladin is an open source dual-pane file manager for Windows which merges the capabilities of Windows Explorer with the well known and easy to use orthodox user interface.
Saladin supports both 32-bit and 64-bit versions of Windows Vista and Windows 7.
Descend is an open source program for drawing 3D surfaces from parametric equations. It uses a custom, very fast language called Misc to calculate the geometry. It also uses OpenGL to render scenes with high quality
Fraqtive is an open source, multi-platform generator of the Mandelbrot family fractals. It uses very fast algorithms supporting SSE2 and multi-core processors. It generates high quality anti-aliased images and renders 3D scenes using OpenGL. It allows real-time navigation and dynamic generation of the Julia fractal preview.