Educational Websites —

Courses
Coursera
EDX
University of Reddit
Lynda

Books
Bartleby
Gutenberg
Librivox
Poem Hunter

Videos
Academic Earth
C. G. P. Grey
Crash Course
Khan Academy
Minute Physics
The New Boston Tutorials
TED
Unplug the TV

Documentaries
Documentary Heaven
Top Documentary Films

Languages
BBC Languages
Busuu
Duolingo
Live Mocha
MemRise
Verbling

Eastern Philosophy and Buddhism
Audio Dharma [ podcast ]
Teachings of Ajahn Chah
Alan Watts Lectures

Music
How to Play Piano
Justin Guitar

Music Theory
Play Bass Now
Teoria

Programming / Development
Code Academy
Coding Bat
HTML Dog
Learn Code the Hard Way
Ruby Monk
Trypython

User Experience Design
UXMas
UX How
UX Myths

DIY/How-To
Howcast
How Stuff Works
Instructables
The Daily Miscellany
Wiki How
Wonder How-To

Math
Math Run
Project Euler
Wolfram Alpha

Cooking
Cooking for Engineers
Cooklet
How2Heroes
Reluctant Gormet