A great website for teenagers where you can find a lot of information, videos, songs, games as well as fun grammar and vocabulary exercises.
LearnEnglish Kids has lots of free online games, songs, stories and activities for children to have fun and learn English too.
Lyrics training is an easy and fun method to learn and improve your foreign languages skills, through the music videos and lyrics of your favorite songs.
Cambridge Exam Preparation
Flo-Joe is a wonderful website for those preparing for PET, FCE, CAE and CPE. You can find there a lot of exercises, strategies and sample exams.
A monolingual English dictionary with many examples, pronunciation, grammatical forms, etc.
Hundreds of free online and printable grammar exercises.