Up until recently, I generally heard programmers complain constantly about the limitations of SQL and RDBMS's, and I heard a lot about object databases. The idea was that programmers would define objects, and the database would provide persistence for the objects. It was (and still is) a nice idea.
Rails took a completely different approach, embracing the RDBMS as the model itself. Rather than creating objects and pushing the design out to the RDBMS, you define the relational structure and allow Rails to extract an object model. If you are doing basic CRUD operations, you may not have to think about SQL again, even in a reasonably complicated app, and the syntax is very clean.
I just love it. And Ruby is like a beautiful flo... oh yeah, didn't want to get negged, better shut up now.