pr0n is interwebese slang for educational programs. These movies, often called vids tend to be freely available on the 'net via torrents or Jamie down the road's FTP. pr0n is alledgedly extremely addictive, and many regular viewers tend to collect as much of it as they can. As they are only doing it to better themselves through education and study we can but applaud their efforts.
pr0n should never be written as porn, because that's smut and things will get confusing.
pr0n contents can vary, but usually contain goats, people from Stoke and industrial sized tubs of margarine. It should also be noted that watching pr0n normally involves the use of industrial sized tube of hand creme.