Udacity is a site which provides you a variety of courses in an easy and efficient way, I’m a software guy so I have learned many software languages from udacity like android, c sharp, cpp, etc
and I found it very much useful. They have a nano- degree program which is paid but there are many courses which are free too. They have video lessons and the most important thing is that there is always a quiz after every lesson, it is a kind of "hands on" on what you have learned till now. It has helped me a lot and I’m completely satisfied with the site. Even the teachers on the videos have done a great job and explain each and every topic so much efficiently.
If you are looking for an online site to learn something, I strongly recommend you to join udacity or at least give it a try. It has a user friendly design and interface and one can get used to it very much quickly.
Hope that helps.
Thank You.