The Australian Crossword Club is a non-profit organization that aims to provide enjoyment and stimulation to the devotees of the crossword puzzle. Their monthly magazine Crozworld is filled with prize crosswords of all types together with lively discussion between the members about the compositions.
It contains interactive tests and exercises for language learners. Their demos contain a variety of fully operative free exercises. Take a diagnostic vocabulary test in English Multilingual site. Also contains interactive crosswords and puzzles for learners of Spanish.