Vocabulary Links

Word Games

http://www.manythings.org/
Level: Beginner through advanced
Description: Manythings.org really does have many things for English learners to enjoy, including vocabulary games such as PhraseDaze, hangman, and many others.

The Compleat Lexical Tutor's English Word Level Tests

http://www.er.uqam.ca/nobel/r21270/levels/
Level: Beginner through advanced
Description: Take this simple online test, from the Compleat Lexical Tutor, and you can judge the approximate level of your vocabulary. The Compleat Lexical Tutor also has lists you can use at each level. Tests your English vocabulary for mastery at the 1000, 2000, 3000, 5000, and 10,000 most basic words levels, plus the Academic Word List. For undergraduate university work, teachers often recommend to work in this order: 1000, 2000, 3000, Academic Word List, 5000, 10,000. 

Learn word

http://www.lextutor.ca/lists_learn/
Level: Beginner through advanced
Description: Full lists of English vocabulary at the 1000, 2000, 3000, 5000, and 10,000 most basic words levels, plus the Academic Word List. For undergraduate university work, teachers often recommend to work in this order: 1000, 2000, 3000, Academic Word List, 5000, 10,000. You can systematically improve your vocabulary using these lists from the Compleat Lexical Tutor.

Idioms

Self-study idioms at Activities for ESL Students (a4esl.org)
Level: Beginner through advanced
Description: Many different self-study idiom learning and quiz activities here. The home page, http://a4esl.org/ is also excellent, with many activities for English learning.