The Internet Raytracing Competition ran for a decade between 1996 and 2006. While no longer active, the content is still available for those who are interested in the early days of software raytracing.
The submission archive is available below.
The IRTC was preceded by Matt Kruse's raytracing competition, which ran from 1994 to 1995.
Questions about this archive may be directed to the admins at www.povray.org or posted in the POV-Ray user forums.