Congo (from content + mongo) aims to be a document based content API and CMS. It uses mongoDB as backend.
It will probably feature pull templates based on Radius template system.

Interesting bits:

  - The documents or contents will be formatted as if they were created by a ad-hoc application, and not spread all over 
  several tables (like in ez publish, expressionengine, drupal...)
  - You don't need to run ALTER TABLE or any kind of migrations whatsoever. That's an expensive operation for production 
  databases
  - You can create similar types based on scopes, like an account, website or user.