Tesseract: Suaerbraten made out of the cube2 sauerbraten assets with the tesseract engine.
This was NOT mostly me. I made a tad of it, but I am really just the guy going around promoting it. You can see all about it here. It is constantly being updated so this may be out-of-date. Github.com I only have it compiled for linux, but you can build it for your platform if you want.