Do not waste time playing games on the computer—practice English and have fun at the same time!
http://www.peakenglish.com/slang/dailySlang.jsp Sign up for slang expressions sent to your email. Also includes business idioms.
http://a4esl.org/ All sorts of fun and exercises!
http://www.awesomestories.com/ Various readings, some with listening included.
http://www.voanews.com/english/2008-03-07-voa17.cfm Voice Of America: read and listen to news.
http://www.voanews.com/specialenglish/index.cfm Voice Of America: listen to news at slower speed.
http://www.englishpage.com/ Primarily grammar, but includes links to listening, reading, etc.
http://grammar.uoregon.edu/toc.html Grammar for writing course.
http://www.englishpage.com/ All sorts of grammar explanations and practice; links to listening, reading, etc.
http://academic.gallaudet.edu/handbooks/writers.nsf Writerís handbook; includes exercises.
http://www.ego4u.com/ EGO—English Grammar Online; includes reading, business, games, etc.
http://www.grammarbook.com/ Grammar and punctuation rules and exercises.
http://www.sheppardsoftware.com/web_games_vocab_sat.htm Vocabulary builder.
http://utminers.utep.edu/micontreras/ Online explanations and exercises.
http://www.eslcafe.com/pv/ Phrasal verbs. (Study a few every day—use them in your writing and speech.)
http://www.englishclub.com/grammar/verbs-phrasal-verbs.htm Types of phrasal verbs: examples / exercises.
http://www.englishpage.com/prepositions/phrasaldictionary.html Phrasal verbs.
http://a4esl.org/q/j/ck/fb-phrasalverbs.html Phrasal verbs exercise.