As a student we are sometimes in a position that we are not able to clearly grasp topic , or missed out some of the courses due to unavoidable circumstances, or learning an entirely new topic, or professor not being able to teach properly or whatever the reason may be. Internet is full of resources for those who need it.A quick search on the topic will return tons of information. Here is list of sites that present university level courses in video and interactive format. There is no best list as new ones come up regularly, or this list might be old when you read it. Khan Academy —The website supplies a free online collection of more than 3,000 video lectures stored on YouTube on various subjects ranging from maths ,science,arts, economics etc.. Code Academy ---It is one of the best place to start to learning to code. It very interactive place, and you can track your progress easily. Udacity ---It is newcomer in this field with courses being bit more complex than the others. But since i...