Open source HTML5 game framework that offers WebGL and Canvas
Self-hosted CMS platform based on the Laravel PHP Framework
Open source library for creative expression on the web, desktop, etc.
CTFs as you need them
JavaScript framework to build game engines, games, emulators and apps
The imaginary eight-bit machine
A complete web framework to create online Fighting Fantasy adventures
3D .NET engine for Windows, Linux, Mac
Educational framework for OpenGLES, OpenCL and OpenAL
Modular Gaming Open Source Persistent Browser Based Game Framework
Powerful html5 & javascript library for creating applications & games.
Formerly CraveJs, it's for creating JavaScript applications and games.