Grammar/self-tests:
http://www.ego4u.com/en/cram-up/grammar/
Other websites:
http://www.eslpartyland.com/#axzz1lqtR7JD4
http://funeasyenglish.com/
http://www.rong-chang.com/
http://www.learnenglish.de/
http://www.manythings.org/
Activities for ESL Students
http://a4esl.org
Conversation Questions for the ESL/EFL Classroom
http://iteslj.org/questions
Dave's ESL Cafe
http://www.eslcafe.com
English Online
ESL Independent Study Lab
http://www.lclark.edu/~krauss/toppicks/toppicks.html
Internet TESL Journal
http://iteslj.org/s/ib/
Self-Study Quizzes for ESL Students
http://a4esl.org/q/h/
Self-Study Quizzes for ESL Students
http://www.esl-lab.com/