Here is an original 15×15 crossword puzzle I constructed, called “A Touch of Math“.
A Touch of Math 2011 – Patrick Honner
I would rate this puzzle as easy, suitable for those without much puzzling experience.
As the title suggests, you don’t need any special mathematical knowledge to complete this puzzle. All of the long clues, and a few short ones, are math-related, but by no means is it entirely mathematical (constructing such a puzzle would be extremely difficult!).
Try it yourself, and feel free to use it with your students.