1. Udacity Udacity is one of the best-known MOOCs (or Massive Online Open Courses) available on the Web, and the content it contains can tutor you on everything from Android apps to social network analysis. Short videos a few minutes in length are punctuated by quizzes and exercises, and once you've signed up for a particular course it can last from a few weeks to a few months (check the information page for each individual course). You can think of Udacity as attending college over the Web, ju