Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and grids. It is based on a hierarchical design targeted at federations of clusters. Ganglia is currently in use on over 500 clusters around the world and has scaled to handle clusters with 2000 nodes....

GPS, the GNAT Programming Studio, is a cutting-edge Free Software IDE that streamlines the interaction between developers and their software. With its intuitive interface, GPS is easy to use, simplifying source navigation and highlighting the fundamental ideas in the program....

OPTv2 is a template engine for PHP5 based on XML language. It focuses on portability and declarative programming, where you specify what you want to achieve, not - how it is supposed to work. Together with powerful syntax, it provides a modern, objective API designed especially for use with popular frameworks....

sventon is a web client for browsing Subversion repositories. It is powerful, straightforward to use, and super easy to install.

OOFEM is an open source multi-physics parallel finite element code with object oriented architecture. The aim of this project is to provide efficient and robust tool for FEM computations as well as to offer highly modular and extensible environment for development....

Greylisting implementation for Postfix,

Qsynth is a fluidsynth GUI front-end application written in C++ around the Qt4 toolkit using Qt Designer. Eventually it may evolve into a softsynth management application allowing the user to control and manage a variety of command line softsynth but for the moment it wraps the excellent FluidSynth. FluidSynth is a command line software synthesiser based on the Soundfont specification....

OSSIM provides advanced geo-spatial image processing for remote sensing, photogrammetry, and Geographic Information Systems. Backed by an active open source software development community, OSSIM solutions have been deployed on a number of critical commercial and government systems....

LÖVE is a Lua-based open-source 2D game engine, the awesomeness of which cannot be questioned. EVER.

A logrotate alternative; easier to use.