I'm trying out DataMapper, one of the Ruby ORM's which can be used with Merb.
I like it so far, its very straightforward, here's an example class that I created to test with Established Sites:
class Es_site include DataMapper::Resource property :site_id, Serial property :modification_timestamp, DateTime property :creation_datetime, DateTime property :description, Text property :title, Text property :site_access_url, Text property :site_storage_path, Text end