This site has lots of interesting short texts, giving instructions on how to do lots of different things (how to fight a cold, how to give up smoking).
Grammarman is a superhero cartoon character. Young learners will enjoy reading the colourful cartoon strips. At the end of every story there is a task to help solve a grammar problem.
This site is very easy to use and has lot's of grammar and tenses explanations and exercises to test understanding. There are also some listening, voabulary and idioms exercises and helpful hints/language for everyday situations.
This Canadian site has lots of grammar practice activities for students in the Grammar Central area. The 'Crazy English' and 'Terrible Teacher' activities are examples of more challenging exercises.
This site provides information on a whole range of grammatical areas presented as a course. Students can read through the grammar explanations in the suggested course order or go straight to the area they are interested in.
This site provides explanations and examples for students to help them use verbs, nouns, adjectives, adverbs, pronouns, conjunctions and interjections correctly.