I’m involved in the development of several Free Software. Most of them are available from the freehackers’ laboratories. Source code is available from this url. The most important ones are listed here.

• Eigen a C++ template library for linear algebra: vectors, matrices, and related algorithms.
• hgactivity a mercurial extension to create a graph of the activity
• Convex Processing a quick and efficient library to perform convex analysis
• Opale very simple accounting for KDE/KOffice
• Zeta Linux Linux ported to a virtual platform

Those software are the ones I like to work with very much, and I highly recommend using them

• KDE : desktop environment for linux and other unices.
• Eigen : modern, fast, beautiful C++ template library.
• Mercurial : A fast, lightweight, distributed source control management system.
• Redmine : Project management web application.
• Gentoo : linux distribution for geeks

Of course, I enjoy using the linux kernel, GNU tools and other common free software as well.