Hi Peter
You could investigate the non-standard Game module.
Crossword is definitely in there:
http://moodle.org/mod/data/view.php?d=13&rid=1196
We have a small demo of the Game module working here:
http://www.elearning.school.nz/course/view.php?id=36
As for pedagogical value of games...
...I think anything that makes learning fun and enjoyable has value!
Stuart
Lesson
Using data from PDF Forms in a Moodle module
ការពិភាក្សាត្រូវបានបិទ ដូច្នេះអ្នកមិនអាចឆ្លើយតបទៀតទេ។