Here is a devotee who is doing KC crosswords (His puzzles seem to be aimed at a bit older devotee):
"Krsna and Balarama learned the art of dressing hair in various styles and fixing a helmet in different positions on the head. They also learned how to set up a theatrical stage, how to decorate dramatic actors with clothes and with flower ornaments over the ear, and how to sprinkle sandalwood pulp and water to produce a nice fragrance... Then They learned how to make and solve riddles. They learned the art of how even a dull student can very quickly learn the alphabet and read books. Then They learned how to rehearse and act out a drama. They also studied the art of solving crossword puzzles, filling up the missing spaces and making complete words."
KB 45 Krsna recovers the son of His teacher
Devotee Generated Crossword Puzzle
While simple crosswords are certainly a good tool for teaching kids, don't assume they are limited to that:
Not Your Mother's Crossword