Some didn't get their books on time...sigh. Also, is there a way to reset a quiz that is set to be taken only once for one or two students to take again?
Nope, and Nope...nothing for individuals...although the fact that the assignment is past due should not prevent them from submitting the assignment. Same for the quiz
If you click on the assignment/quiz and click "Update this Assignment/Quiz" you can reset the due dates. As for the quiz, open it, let 'em take it, and then close it again, and chances are that no one will ever know.