Create your own course to memorize anything you want. Flashcard-based, with text formatting, with images, with multiple flashcard types.
Spaced-repetition app, focused on ease and speed of creating own courses, with flashcard formatting (LaTeX, image insertion) and cloze deletion flashcards.
Anki - Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Clever - syncing between education applications for K-12 schools
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
AnkiDroid - Memorize anything with AnkiDroid!
Claroline - Claroline is a collaborative eLearning and eWorking platform.