Cross-Platform C++ GUI Library
Free game engine for development of desktop, mobile, and web games
Cross-Platform C++ 2D/3D game engine
RTSish Game Engine
An open process control and laser engraving software solution
A wxWidgets GUI Builder
Tools for Super Tux Kart server operators
The most minimal cross-platform GUI library
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
3D C++ Game Engine - yet another open source game engine
2D ARPG Engine
A fast, powerful and adaptable GUI solution
Windows XP reimplemented on Nintendo DS
Turn based Civ-like strategy game
A Lua and XML Graphical User Interface
Karaoke effects creation tool with ASS and Lua.
Simple, fast, flexible gui for irrlicht and other...