Teachers often give crosswords based on reading texts to their students.
This is a good idea, but an even better idea is to have students in small groups work together to create crossword puzzles based on texts, which they will give to another group to solve. I have done this with different texts in several classes and each time my students have applied themselves with great concentration to the task. It is important that you have students do this in steps. The first step is to provide the students with a text and a small sample crossword puzzle based on the text you have made. Have students solve the puzzle.