Crazy Eddie's GUI (CEGUI) system is a graphical user interface C++ library. It is designed particularly for the needs of videogames, but the library is usable for non-game tasks. It is designed for user flexibility in look-and-feel, as well as being adaptable to the user's choice in tools and operating systems.
Read more about CEGUI: Configurability, Tools, Rendering, Resource Management, Memory Management, Scripting, Look and Feel, Animation, Unicode, Library Dependencies