ioquake3 (or ioq3 for short) builds upon id Software's Quake 3 source code release. It cleans it up, fixes bugs, and adds features. Its goal is to be the Quake 3 distribution upon which people base their games and projects. Its design goals include optimizing the engine for playing Quake 3: Arena, Team Arena, and all popular mods. This distribution of the engine has been ported to many new platforms. While it doesn't have PunkBuster (and never will), it does provide more security for servers and clients by way of various bugfixes which aren't in id's client.
San Le's Free Computational Electromagnetics (SLFCEM) is a package of scientific software for use in computational electromagnetics. Command-line driven calculation engines are separate from the GUI components and can be used independently. It includes two of the basic finite elements types, 4 node quad and 3 node triangle. Each element type has a unique GUI specific to the element. Modal analysis for solving the waveguide problem is done using edge based elements. There is also code for generating edge connectivity. The algorithm used is a combination of Lanczos for tridiagonalization of the system, as well as QR to calculate the resulting eigenvalues. In addition to skyline storage and LU decomposition, calculations are also made using the Conjugate Gradient Method.
TSDL was written for the turn-based strategy game "Turious", but is a stand alone library. It provides a number of useful widgets and event handling functions. Its widgets include container, label, button, text, numbox, checkbox, and console. All of the widgets can be given individual background images and custom text. Containers and widgets can be shown and hidden individually, and will retain their visibility state. The library uses OpenGL for rendering, allowing it to be used in 3D games as well as 2D.