EdX is one of the more unique education apps. Instead of offering courses from professionals, it offers courses from actual colleges. You won't get a legitimate college degree out of them. However, there are courses in computer programming, engineering, history, psychology, nutrition, statistics, and hundreds of others. It features online or offline video lectures, course announcements and handouts, and various tutorials. All of it is completely free. Anyone looking for higher education should have this app right now.