I stumbled across Quizlet, a website that lets users learn factual information with flash card exercises. People can use the flash card sets that are already on the site, or they can create their own. The games and quizzes are simple but addictive. Want to learn capital cities of the world or improve your Arabic vocabulary? Quizlet is a quick and easy way to do it. I can see an assignment in which students design content on Quizlet for a particular topic, which they then share with other students as a study aid. Or students could compete against each other in class to see who scores the highest on tests in the shortest amount of time.

(As a disclaimer: I have no financial interest in this company)