16 Brain Pickings
Brain Pickings. If you love to know about anthropology, technology, history, psychology then Brainpickings is the best place for you. The website might look complicated first, but give the website ten minutes and you will fall in love with it.
Lumosity. You might be familiar with this name because there is a popular Android app available on Google Play Store which is used by many users. This website has some scientifically designed games which will train your brain.
Quora, Well, Quora is a question & answer site where users ask lots of question. If you are smart enough then you can answer it, or if you want to be smart then read out other answers from smart people. You can learn anything from Quora.