Expressive middleware for node.js using generators via co to make web applications and APIs more enjoyable to write. Koa's middleware flow in a stack-like manner allowing you to perform actions downstream, then filter and manipulate the response upstream.
Sails.js make it easy to build custom, enterprise-grade Node.js apps. It is designed to mimic the MVC pattern of frameworks like Ruby on Rails, but with support for the requirements of modern apps: data-driven APIs with scalable, service-oriented architecture.
Opa is an open source, simple and unified platform for writing web applications. All aspects are directly written in Opa: Frontend code, backend code, database queries and configuration. And everything is strongly statically typed.
Both Knockout.js and Backbone.js have their strengths and weaknesses, but together they are amazing! With Knockback.js, you can use the strong ORM provided by Backbone and create dynamic views using Knockout bindings.