Jeff atwood, of CodingHorror and Stackexchange fame, has just released a new open source project, Discourse, which aims to replace current forum software.
There are a lot of interesting features, that I'm going to steal. I guess I have to rewrite the specifications for the next version of this site :).
I don't think I could use Discourse directly, as it is written in Ruby and knowing mister Atwood disdain for php. Plus, I like to code things myself, which is why I don't use Disqus, for example.