Start with these

1. Synonyms and Antonyms
Synonym: big = huge
Antonym: big ≠ small

2. Freetime Activity Quiz

3. American English VS. British English
Do you know which words mean the same thing? (for example, British "chips" = American "fries")

4. English sayings -- do you know them?

5. More sayings

6. Even more sayings

7. Do you remember the months in English?

Choose something you're interested in and do the exercises.