Create a form in a Google Docs spreadsheet and send it out to anyone with an email address. They won't need to sign in, and they can respond directly from the email message or from an automatically generated web page.
Creating the form is easy: start with a spreadsheet to get the form, or start by creating the form and you'll get the spreadsheet automatically.
Responses are automatically added to your spreadsheet!
Tip: To automatically collect a respondent's username in a form on your domain, check the 'Automatically collect respondent's username' checkbox at the top of your form. When the form is saved, a new column called "Username" will be added to your form's spreadsheet. Respondents' usernames will appear there.
Introduction to Google Forms
10 Google Forms for the Classroom