Daniel Pohl from Intel has published a new article about his work and progress with ray tracing rendering. This article is intended to be a follow up article to one released about a year ago.
A lot of things have changed since then. Real-time ray tracing for desktop machines is just around the corner, he says.
Ray tracing is a rendering technique that generates a 2D image out of a given 3D scene.

If you are new to the topic of ray tracing there is also a introduction to ray tracing. The article is full with examples and described pictures/diagrams, examples using Oblivion, Portal, Quake 3 & Quake 4.

Article on PC Perspective

Related links:
Intel developed Raytracing-Engine for PC
Quake 4: Ray Traced Project @ pcper.com/article
Quake 4: Raytraced