Attached Link: http://www.softlab.ece.ntua.gr/~jpanta/Graphics/Kerkythea/

There's a little-known renderer called Kerkythea (it's Greek, no really, it is!) which is still in the early stages of development but already very impressive and pretty easy to use (as renderers go). It has been built from the ground up as a daylight/global illumination-type renderer (rather than having GI tacked on afterwards as so many others have done) and it is very fast. The interface isn't pretty (yet) but it is coming along in leaps and bounds. Considering it's being written by one guy in his free time the rate of progress is startling. And it makes very pretty pictures - check out the gallery on the Kerkythea site