SPF : A lightweight JS framework for fast navigation and page updates from YouTube
RequireJS : RequireJS is a JavaScript file and module loader. It is optimized for in-browser use, but it can be used in other JavaScript environments, like Rhino ...
SoundManager 2 : Using HTML5 and Flash, SoundManager 2 provides reliable cross-platform audio under a single JavaScript API.
WebPagetest : Run a free website speed test from multiple locations around the globe using real browsers (IE and Chrome) and at real consumer connection speeds.
boomerang : boomerang is a piece of javascript that you add to your web pages, where it measures the performance of your website from your end user's point of vie...
InstantClick is a JavaScript library that dramatically speeds up your website, making navigation effectively instant in most cases.