What blog engines written in Ruby do you know? Let's create a list of all Ruby blog engines as a community wiki.

I kindly ask to include the following in your answers:

• blog engine name
• link to official website
• link to screenshots or live demo
• gem install gem-name (if there is one)
• features, for example:
  • has plugin engine?
  • has themes?
  • has administration panel?
  • anything worth mentioning

Not an endorsement, just report the facts. This will make the answers very helpful to visitors. :-)

Please mark your answer as a community wiki so that anyone is able to refine the description, add links, etc.

It seems noone asked the question before. Found some which aren't the thing I'm really asking for.

• Ruby CMS/blog: Mephisto vs. Radiant (choosing which is better)
• Ruby Based Blogging Engine (asking just about rack-enabled blog engines)
• Blog Engine for Rails Application (limited to Rails)