BZFlag is a 3D, multiplayer, tank battle zone, capture the flag game that pits players against each other in a networked environment. It runs on Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix, Solaris, and others. An OpenGL accelerator is highly recommended, but it is playable with 3D in software.
QCad is a powerful but easy to use 2D CAD program for Linux, Windows, and Mac OS X. It uses DXF as its standard file format. While other CAD packages are often rather complicated to use, QCad tries to stay comfortable, and even an absolute beginner can create professional drawings with a minimum of effort.
cz2cz tools is software for converting texts between various charset encodings that are used in the Czech language. The most important feature is autodetection of the most-used encodings (UTF-8, ISO-8859-2, Win-1250, cp850, and Kamenickych). There are both console non-interactive (text-based) and interactive (curses) applications. cz2cz also allows you to convert characters with diacritics to TeX (LaTeX) conventions. The interactive part of cz2cz tools can be used for quick manual complementing of diacritics to texts.