OpenBlox lets you make games with a built-in physics engine, Lego-like building blocks, and a scripting language called Lua. Once you've made a game with OpenBlox, you can pack it into a single file with one mouse click, and share your game with anyone you want.
Zen Worlds is an object oriented C++ virtual worlds / MMO game engine framework. This project includes Zen Engine game engine client, Zen Enterprise, an Enterprise Service Bus, and a C++ Application Server, and Zen Studio, a game development IDE.