JavaScript - Lightweight, interpreted, object-oriented language with first-class functions
BlitzPlus - Create 2D Games for Windows.
Qt - Powerful, flexible and easy to use, Qt will help you not only meet your tight deadline, but also reduce the maintainable code by an astonishing percentage.
Cocos2d-x - Cocos2d-x is an open-source and cross platform open source free 2D game engine for mobile game development known for its speed, stability, and easy of use
CKEditor - Real-time collaborative future-ready rich text editor
Phaser - Desktop and Mobile HTML5 game framework. A fast, free and fun open source framework for Canvas and WebGL powered browser games.