If your school uses Google Apps for Education, when you have students take quizzes that you've created through Google Forms, have your students sign into their accounts before taking the quiz. That way you will capture their email addresses and be able to quickly email grades to them after you have run the Flubaroo script to grade the quiz. If your school doesn't use Google Apps for Education you can still require email addresses by making "email address" a required question on the quizzes you create in Google Forms.