PLIB is a set of libraries to write games and other realtime interactive applications that are 100% portable across a wide range of hardware and operating systems. It's used by Majik3D, FlightGear, and others, and includes libraries for GUI widgets, sound replay, geometry, scene graph, joystick, and fonts/text.
The Torque Network Library is a robust, secure, and easy-to-use cross-platform C++ networking API designed for high performance simulations and games. It features a UDP- based connection architecture with DoS prevention functionality, different types of data guarantee, bit stream compression, server object replication and updating, and a simple, highly space efficient RPC mechanism. It includes a deterministic application journaling replay function for eliminating hard to find networking bugs.
The OpenAI site is centered around an Open Source project and community involving artificial intelligence. The project itself is the creation of a set of tools that are considered to be models of human intelligence or biomimicry. These tools are intended to be integrated into applications or used stand alone for research.