RubyOnRailsBlog.com, an 'unofficial Rails blog', has taken a look at twenty different Rails-based content management systems. These CMS tools and plugins are covered: Radiant, Typo, Mephisto, Streamlined, Rubricks, Ajax Scaffold Generator, Eribium, RCMS, Admin Pages CMS, Spread, Pimki, RealApps, DateBocks, ClockingIT, Juggernaut, and Comatose.
The content management systems range from simple plugins that you can use in your own Rails applications through to entire stand-alone Rails applications.