4chan Source Code

Is there anywhere to download the source code of 4chan/other image boards? I'd like to see it just out of curiosity and to possibly set one up for myself and friends.

Hi, I have a Perl imageboard script called Kareha that works without requiring a database; it's perfect for my old server.

You can download Kareha here:
http://wakaba.c3.cx/
and you can download my patch with modifications to make the imageboard at least look more like 4chan here:
http://tweek.no-ip.org/stuff/kareha-4chan.patch