http://www.memrise.com/ A wide range of languages and subjects and easy to use. Subscription is free.
http://www.jimmyp.me.uk/ A good variety of interactive games
www.languagesonline.org.uk A range of grammar and vocab games.
http://www.funwithlanguages.vacau.com/ Lots of great exercises.
http://oye.languageskills.co.uk/index.html Free after 4 p.m and has listening files as well as games.
http://www.trentu.ca/academic/modernlanguages/spanish/masarriba/ Has a good mix of grammar and vocabulary exercises.