polyfill : polyfill makes web development less frustrating by selectively polyfilling just what the browser needs. Use it on your own site, or as a service.
enquire.js : A lightweight, pure JavaScript library for responding to CSS media queries.
jsPDF : A library to generate PDFs in client-side JavaScript.
Tracery : A story-grammar generation library for javascript. Write grammar objects, get generative stories.
yepnope.js : A Conditional Loader For Your Polyfills!
Add Clippy or his friends to any website for instant nostalgia.