TodoMVC is an awesome project by Addy Osmani and Sindre Sorhus. In their own words:
Developers these days are spoiled with choice when it comes to selecting an MV* framework for structuring and organizing their JavaScript web apps.
Backbone, Ember, AngularJS, Spine… the list of new and stable solutions continues to grow, but just how do you decide on which to use in a sea of so many options?
To help solve this problem, we created TodoMVC – a project which offers the same Todo application implemented using MV* concepts in most of the popular JavaScript MV* frameworks of today.
The website now boasts of implementations using over three dozen frameworks. And I decided to pitch in using Mojito by Yahoo!