What We Love: Codeacademy
Their site structure is clean, and the lessons themselves are well structured and push you to learn by coding using trial and error throughout every lesson. They offer a "Hint" option - sometimes you just need to use it. One of our female staff wishes she had a "hint" option when she is out with friends and men approach her and just don't get the "hint."
Go and check out this awesome site now at http://www.codecademy.com