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.

I made my own version of 4chan and called it PHP chan, I'm still working on it though.

You can check it out at http://phpchan.tk/

And ignore the "current users" thing that says there are 500+ users currently online, I need to fix that as in reality, no one is there.