Game engine that has been iterated on over the years with some nice additions by some nice people.
I use this engine to play with rendering techniques and some graphics infrastructure - no more no less. This engine can be used to create a game -- checkout Battle Royale with Cheese to see that. But for the most part you won't find complex AI, animation, gameplay, or art in this engine. You will find a collection of fun rendering techniques.
Full information and development details can be found at my blog
And each project has a README with visuals if you want to poke around.