Self-hosted game stream host for Moonlight
One of the best Prodigy hacks
Complete Open Source and Modular solution for MMO
Open Source MMORPG Framework
A Minecraft mapping tool that creates 3D models of your Minecraft
Experimental PlayStation Vita emulator
PoC Minecraft client written in Javascript
LSJ-Server-Terra (Java Multipurpose Sever connected with MariaDB)
Azuriom is a complete open-source web solution for game servers
Free, Secure, Distributed, Modern Control Panel for Minecraft
Build multiplayer web games played by millions
Repository for the Goonstation branch of SS13
PufferPanel is an open source game server management panel
A permissions plugin for Minecraft servers
The Tiny JavaScript Game Engine That Can!
CTFs as you need them
Python MUD/MUX/MUSH/MU* development system
You can make it - Open Source MMORPG Platform
Classic America's Army
Arianne is an engine to develop multiplayer online games like Stendhal
The ultimate cataloguer
FlightGear Flight Simulator: free open-source multiplatform flight sim
GameServer is a sophisticated, game server designed for online games
A planetarium software that shows a 3D simulation of the night sky