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 wouldn't recommend 4chan's buggy and broken code. Instead, try something new. pychan is a very light, completely AJAX-powered imageboard written in ~150 lines of Python and ~450 lines of JavaScript. All requests return JSON (like thread listing, thread display, etc.). If you are wanting to play around a little with a new imageboard, this is probably better for you.

Browse source: http://azabani.com/cgit.cgi/pychan
Clone source: git://azabani.com/pychan
Reference implementation: http://neckbeardchan.azabani.com/