SLDG: Framework for implementing numerical solvers based on the semi-Lagrangian discontinuous Galerkin method. Vlasov solvers for both clusters and GPUs are available.
Eigen: Framework for the easy and efficient implementation of dynamical low-rank algorithms (currently supports multi-core CPUs and GPUs).
Slider: A program to generate presentations, in the pdf format, from source files based on a markdown like syntax. Support for LaTeX formulas, column layout, references, source codes, etc.
Nothon: A desktop wiki geared towards scientific applications. Thus it includes strong integration with Latex, plotting (gnuplot or matplotlib), viewing data files, etc. Together with Zoltán Vörös.
Desktop Data Manager: A clipboard manager that can handle images as first class citizens. A, tightly integrated, screen capturing tool and a download manager is also available. Written in C# using Mono (last update: 2008). Articles about DDM: Linux FUD lifehacker linux.com Debian Admin
Electroutil: Software for drawing logic diagrams and looking up the pinout for a number of integrated circuits. Developed during high school (last update: 2004).
Calculus Java applets: A number of educational Java applets covering concepts from calculus. Originally implemented by Markus Unterweger.
Young university Wii controller: Simulation viewer that uses a Wii to track head moevement and generate a 3D effect. This is done using safety goggles, where the visible light LEDs have been replaced by LEDs emitting infrared light. Three simulations are available: hydrogen atom, fluid flow over an airfoil, and wave dynamics (implemented by Christian Bargetz). Written in C++ using OGRE.
Space Wars: Last Resistance: Space shooter game developed during middle and high school. It includes 8 levels and 5 opponents. Written in C++ using DirectX on Windows. Image of the day (zfx, german)