Google Forms are excellent options for online quizzes, surveys, contact forms, and any questionnaire. You'll get quick responses that are easy to sort, and easy to grade. If you are using objective questions, check out the tutorial on Flubaroo. This will automatically grade your responses for you!
Directions for creating forms and using Flubaroo
These directions are based on creating forms in a Google Apps for Education Domain. The example is FCSchools.net, but the directions should work with all Google Apps domains. If you're using a basic gmail account that isn't associated with a Google Apps domain, the directions will be the same with the exception of the checkboxes at the beginning.
How do you use Google Forms?