Simplest possible examples of HTML, CSS and JavaScript.
#reference
tiimgreen/github-cheat-sheet
A collection of cool hidden and not so hidden features of Git and Github.
CSS Vocabulary
Great resource to make sure you’re calling things by their correct name in CSS-land.
A List of Foundational JavaScript Tools
A List of Foundational JavaScript Tools
Excellent list of tools which are recommended to students studying Javascript.
PHP: The Right Way
There’s a lot of outdated information on the Web that leads new PHP users astray, propagating bad practices and insecure code. PHP: The Right Way is an easy-to-read, quick reference for PHP popular coding standards, links to authoritative tutorials around the Web and what the contributors consider to be best practices at the present time.
Learn X in Y Minutes
See samples of different programming language and their syntax, written in those languages.
js-assessment
…a set of tests that can be used to assess the skills of a candidate for a JavaScript position, or to improve one’s own skills.
Git Immersion
Git Immersion is a guided tour that walks through the fundamentals of git, inspired by the premise that to know a thing is to do it.
OverAPI.com
Cheat sheets/references for all sorts of programming languages.