VocabSushi is an online vocabulary building service that helps you learn new vocabulary words through the context of real-world sentences from recent news articles.
Conceived and created by Jeff Novich, an SAT tutor in New York City, it is interesting for students studying for standardized tests, and is also perfect for anyone looking to expand his or her vocabulary to communicate more precisely.
You can sign up for free. A pro (paid) service for teachers is also available (video).
On Twitter: https://twitter.com/vocab_sushi