Hi,
Couch_potato is a nice gem. It provides a nice document oriented api and relies on couchrest.
It also provides some validation and callbacks that allow you to use those features just like in activerecord and other ORMs.
You can add some validations , callbacks by using SimplyStored/Couch ( on github) wich is build on top ov Couch_potato and couchrest.
The simply_stored also adds some basic relations support (belongs_to, has_many ... ) but I personally don't find this feature really interesting and well implemented.
I think that couch_potato is your best way into joining rails and couch.
