The Raytracing Episode: A Confession, What Raytracing Is, DKBTrace, The Overnight Render, DKB and POVRay, The Pac-Man, Anything for a UNIX Prompt, Gandalf, Supermarket Gang, Pixar's Tools, A Missed Boat With No Regrets.

DKBTrace/POVRay has a website here: http://www.povray.org/

The original creator of the POVRay Pac-Man Render: http://vs.iki.fi/raytrace/

Here's the Pixar Presto demonstration I'm talking about (I was in the back of the room): https://www.youtube.com/watch?v=hnFSVx7NhmM

The POVRay Wikipedia page is (as of this writing) a good overview of the lineage and aspects of the program.