Believe it or not, midterm season is upon us, and Quizlet is a little app aimed at keeping you in the teacher’s good books. Essentially a flashcard app, Quizlet is great for vocabulary, geography and other quizzes. One big drawback to this app is that you can’t create flashcard sets from your phone — you’ll have to head to the service’s Web site for that. Still, having your study materials at your fingertips for those little breaks during soccer practice or rehearsal is worth having to put on a little prep ahead of time. Free, for iOS devices.