This is my latest ray tracer. It's a monte carlo path tracer using octrees for optimization.
I haven't released the source of this thing since I "borrowed" some intersection testing code and there was no license given in the file.
Anyway here are some images.
Render times are around 2h with 512 samples per pixel at 1280x1024 for a ~1M triangle model on a 3.1ghz Core2.