I recently created a presentation on the Moodle Quiz, so I thought it worthwhile me sharing it here.
The quiz is really a powerful tool in the Moodle toolkit. If you are interested in learning more about it, below are some links to the Moodle Docs site and the Moodle forums.
Moodle Quiz Activity Docs: http://docs.moodle.org/en/Quiz_module
Different question types Docs: http://docs.moodle.org/en/Question_types
For discussions on the Quiz Activity check the Moodle Forums