Ask HN: Is source code for this site open source?

Yes:<p><a href="http://github.com/nex3/arc/blob/master/news.arc" rel="nofollow">http://github.com/nex3/arc/blob/master/news.arc</a><p><a href="http://arclanguage.org/" rel="nofollow">http://arclanguage.org/</a>