Quizes, Tests and Games.
Test yourself on your knowledge of abbreviations with this quick quiz - http://www.usingenglish.com/quizzes/414.html
Play Hangman here - http://lapasserelle.com/games/hangman/hangman1.html
Place words into semantic groups with this online card game - http://www.english-online.org.uk/games/categories.htm
Use this quiz to test yourself on plurals - http://www.usingenglish.com/quizzes/356.html
For tons of quick quizes and tests check out this site - http://www.usingenglish.com/quizzes/
EduFind also has a great archive of quizes relevant to the topics covered here and in the first unit of english language - http://www.edufind.com/english/englishtests/list_of_english_tests.php
For more in depth tests try - http://english-quiz.net/