Recommended Learning Resources on Github:

Sergey Bolshchikov is an active contributor, including this list of great JavaScript videos:
JS Must Watch

Kyle Simpson, better known as Getify, is writing a series of books on JavaScript. Check out the latest work in progress:
You Don’t Know JS

Scope and Closures Chapter 1
Scope and Closures Chapter 2

Scope and Closures Chapter 3

Scope and Closures Chapter 4
Scope and Closures Chapter 5
Scope and Closures Chapter 6

Julien Bouquillon, a.k.a. Rovolunet, has produced a list of free JS and Python ebooks:
JavaScript Books
Python Books

Victor Felder, a.k.a. vhf, has created a project listing a huge amount of free programming books:
Free programming books

Elijah Manor on JavaScript code smells: http://elijahmanor.github.io/talks/js-smells/#/

Web RTC
Demos and samples
For an introduction to Web RTC see my performance page

Web GL
Code samples from O’Reilly Web GL book

Microsoft open source products:

Entity Framework 7
Sublime Plugin for TypeScript support

Facebook open source products:

React

Google open source products:

Traceur
Many others featured in the A-Z of JavaScript

IBM open source projects:

IBM

If you are interested in .NET Core projects on Github, see this guide by Mark Rendle