Single Page Applications with Node.js

That would be awsome a node.js framework which helped to make this kind of single page apps. I've been thinking about that since I discovered backbone.js.

I'd love to define models just once and that they would work server side (using a ODM like mongoose) and client side (using backbonejs).

Is there something like this out there? If not maybe I'll try to make it this summer (having final exams at the moment).