Grammar Practice Sites/ Rules and Exercises
http://www.prenhall.com/bluepencil/
http://www.chompchomp.com/exercises.htm (if they ask for a password, just hit the close (x). The site will come up automatically.)
http://owl.english.purdue.edu/handouts/grammar/
http://a4esl.org/q/h/grammar.html
http://grammar.ccc.commnet.edu/grammar/
http://grammar.ccc.commnet.edu/grammar/quiz_list.htm (This is the quiz section for this excellent site.)
http://www.bedfordstmartins.com/hacker/exercises/
http://www.ucalgary.ca/UofC/eduweb/grammar/
http://grammar.uoregon.edu/toc.html
Good practice for apostrophes:
http://depts.dyc.edu/learningcenter/owl/apostrophes.htm
http://www.bristol.ac.uk/arts/exercises/grammar/grammar_tutorial/page_52.htm