Both of these have pretty vague descriptions,
Backbone.js gives structure to web applications by providing models with key-value binding and custom events, collections with a rich API of enumerable functions, views with declarative event handling, and connects it all to your existing API over a RESTful JSON interface.
and Boilerplate.js,
BoilerplateJS provides reference architecture to take the pain out of large scale JavaScript development. BoilerplateJS is a collection of product engineering patterns, and some solid integrations of industry-leading JavaScript libraries.