DruMVC

A simple drum machine built in the major Javascript frameworks (Angular, React, AngularJS and Vue).
Source.

React Basic Sequencer

Very basic sequencer built with React.js.
Source. Redux version.

React Weight Chart

Weight tracker built with React.js and Chart.js
Source.

Backbone Maze

Implementation of breadth-first search algorithm for path-finding in Backbone.js.
Source.

Backbone Tetris

An implementation of Tetris in Backbone.js.
Source.

Lots more on Codepen.