I am writing a 3D rendering engine from scratch - ie, it doesn't use OpenGL, DirectX or anything. It's pretty useful as it is but I'm still developing it. I thought it might be useful for anyone wanting to create a 3D game without using external programs like OpenGL. You can download the code with example projects here
http://www.geocities.com/peter_bone_uk/engine3d

I made this simple example with it