Open Source MMORPG Framework
CTFs as you need them
Arianne is an engine to develop multiplayer online games like Stendhal
JavaScript framework to build game engines, games, emulators and apps
Java Settlers
A synchronisation component for p5.js
3D .NET engine for Windows, Linux, Mac
AutoTeach makes kids study and learn in exchange for internet access.
Open Source Virtual World and MMOG Development Platform
Investigo - DX9 Performance and Debugging Toolkit
An HTML web game platform
Cross-platform 2D game engine
Game framework on top of Python, Panda3D and Twisted
Atlarius is no longer under development.