Memrise- Memrise is the place to go for your vocabulary retention. There are a lot of courses on almost every language, including ones that are "fictional" (Klingon, anyone?). You have your options between more standardized courses based on popular textbooks, vocabulary frequency lists, and less expected vocabulary collections with naughtier words or translations of works. What makes this app great are memes and gamification. The app has a learning method that relies on creating funny or bizarre associations with the studied words. Memes come to play with this method of teaching, and the everyone in the community can add their own! Learning, revising and creating memes is a source of points that help you advance in the Memrise hierarchy of users (which ranges from Membryo to Overlord).