Blender 2.5 alpha was released a short while ago, and this first testing release of the 2.5 series comes packed with lots of improvements and changes. Obviously, since this is an alpha release, there are some missing or incomplete features, but development has continued alongside the Durian project, and already a lot of new features have been added. One of these new features is Indirect Diffuse Lighting for Aproximate Ambient Occlusion.