I have always been a Cruciverbalist, lover of Crossword Puzzles.
Putting that love together with my data skills, a crossword dictionary were a natural fit. It's a much simpler model than the Quotes database, just three tables: Answers, Clues and a link table. Quite the thing for introducing the concept of data normalization in a way that most people can easily grasp.
Over the years, however, I have added to the list of clues and answers, allowing my simple database to become more useful as a Dictionary. I'm in the process of adding Elastic Search support to it to expand on the ease of use. And a PDF version of the full database as a printable Crossword Dictionary.