Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).
TacitPixel (formerly libTAP ) is a prototyping system for virtual reality and augmented reality applications. It runs on a variety of platforms. RAP (rapid application prototyping) is done through the Lua interface, which mirrors the C++ namespace as closely as possible. libTAP has a small but distinctive feature set, focused on prototyping of realtime 3D simulations.
The Crate Game Engine is a game engine that is designed to make creating games trivial. The rendering and scripting engines are removed from the game engine to make the specialization of games as easy as possible. Currently, scripting support is implemented to allow a Lua script to be put directly in the game file, which can be validated as XML. Multiplayer text based adventure-style games can be played with the existing console rendering engine.
World Domination is a real-time strategy game that uses the Stratagus engine and was inspired by the Axis and Allies board game. It is unique amoung RTSes because it does not require you to havest resources. Instead, you receive money based on how much territory you occupy. This allows the focus of the game to be on combat and not the management of workers.