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.
Penumbra is a first person horror adventure focusing on story, immersion, and puzzle solving. Violence and combat are hardly an option: the player has to use wits to guide Philip through his final test, which makes the series unique in offering a truly dangerous and terrifying experience. Played from a first person perspective and powered by a 3D engine utilizing cutting edge technology, Penumbra is a true advancement to the adventure genre. The unique physics system allows for true environmental interaction: The player can open drawers, pull levers, pick up objects and manipulate those objects in 3D space, all using natural mouse movements. This creates a highly interactive and immersive game world.
The Open Game Libraries is a collection of separately usable C++ libraries for creating games. It provides OpenGL window management, zip file management, OpenAL audio management, a developer console window, input management, bitmapped fonts with Unicode and kerning support, image loading and saving, model loading and importing, and generic classes and objects for game development such as math and text processing.