C/Invoke is a library which can call C functions at runtime with no prior knowledge of the function prototypes. This capability is used to allow any language to call native libraries without writing a separate module in C, similar to the P/Invoke functionality of the .NET framework.
Infon Battle Arena is a networked multiplayer real-time programming game featuring little creatures fighting for food. You upload your Creature Code (written in Lua) to a game server using a telnet Interface. The game server then runs your code. The graphical client can be used to watch running games or replay recorded games.
Renoise is a sophisticated music sequencer and audio processing application. It's an all-in-one music production environment for your personal computer. Based on MOD tracker software, its primary use is the composition of music using samples, (in WAV, AIFF, FLAC, Ogg, and MP3 format), plug-ins, and MIDI/OSC sequencing of VSTi/AudioUnits soft synths.
LuaRocks is a deployment and management system for modules in the Lua programming language. It aims to provide facilities for Lua such as those from module systems of other scripting languages, such as Ruby's RubyGems or Perl's CPAN. LuaRocks allows Lua modules to be installed as self-contained packages called "rocks", which also contain version and dependency information.
Scrupp is a 2D engine that uses OpenGL for hardware-accelerated visualization. All of its functionality is exported to the Lua programming language. Using Scrupp means writing Lua scripts. It features support for movies and networking and enables run-time image creation using Cairo.