RadiantCMS has been getting a lot of press in the Rails world lately as the first, interesting Rails powered CMS (it's open source too), but now comes Comatose, a 'micro CMS' that works as a Rails plugin, allowing you to easy integrate it with your own application. As Matt McCray, the developer, says:

Lately, I’ve had a recurring issue arise on my projects: They generally require a few content pages. Nothing fancy. Just a privacy policy, terms & conditions, an FAQ, that kind of thing.

I don’t really want to make these static HTML pages. They are likely to change at some point, especially the FAQ. Plus, I’d like to have them leverage Rails’ layout support. At the very least, I’d like to have them easy to re-skin.

That said, I don’t want to spend the time integrating an actual CMS system into the application. And really, for just a few pages, it’s too much.

I wanted an easier way. Something that was tiny, simple, and lightweight. Something I could drop into existing applications. In short; a micro CMS plugin.

It's easily mountable with routes, easy to install (a regular plugin - a 4 line install process!), and it seems to be developing a lot of fans pretty quickly.