I recently finished the first usable iteration of some node.js blogging software, which I'm calling nodelog. You're seeing it in action right now!
The reasons I created this in the first place are are slightly bizarre. Firstly, I was running out of resources on my VPS, mostly because PHP and WordPress are rediculous memory hogs, but also because I was simply running too many subdomains/sideprojects/etc. Something had to be done to free up some resources.
Secondly, there has been a bunch of hype around node.js recently, and I'd been waiting for an opportunity to try it out. What better way than to write some blogging software. Two birds with one stone!
As it turns out, node.js is really great, has a huge whack of libraries for things like routing, middleware, and template rendering, and is fairly lightweight.
Check out the project on github.