Babbel is the new way to learn a foreign language. The comprehensive learning system combines effective education methods with state-of-the-art technology. Interactive online courses will improve your grammar, vocabulary and pronunciation skills in no time. You'll make fast progress and have fun doing it.
This web site is for people studying English as a Second Language (ESL) or English as a Foreign Language (EFL). There are quizzes, word games, word puzzles, proverbs, slang expressions, anagrams, a random-sentence generator and other computer assisted language learning activities. Even though the primary focus is for ESL, native English speakers may also find some interesting things on this site. This site is non-commercial and has no advertising. TESL/TEFL teachers may want to recommend this site to their students.
Quizzes, tests, exercises and puzzles to help you learn English as a Second Language (ESL)
This project of The Internet TESL Journal (iteslj.org) has thousands of contributions by many teachers.
I like it, but I prefer free.
Paper Rater is free, no strings attached, and seems to perform all the same functions if not more. Additionally, it offers instruction in some areas that might be weak, such as vocabulary. http://www.paperrater.com/