Tried it; Liked it;

I don't say these are the best out there on the Internet (a single lifetime is not enough to surf the entire Internet... well at least not in this decade), but here is a list of computer & science resources that I found out to be quite useful:

1) Solo learn and code academy - Skip to the interesting content if you already know the basics by taking a test. Good if you are new at a language and want to get an idea how things work in that language (syntax & core features)

Courses offered: Web development, programming languages, etc.

2) Udacity -

Courses offered : 

Official - Android courses by Google.

Other - Git and GitHub

3) EdX - 

Courses offered : 

Featured - Harvard's CS 50(taught by David J Melan - Probably the best CSE teacher out there), Linux by The Linux Foundation. (It's a long course and can get a bit boring, but it sure covers a lot!)

4) Coursera - I occasionally surf their courses, but didn't find anything appealing yet!

###Cool stuff###
YouTube: Ted-Ed, ASAPscience
Also if you have plenty of free time check out: Veritasium and Vsauce (Although their videos can get a bit lengthy, they sure are interesting!)

P.S - All the above-mentioned courses are free. The only thing you need to pay is your Internet bill.

**The list is dynamic. Tell me that websites that work for you in the comments**