The quiz itself is here. If you've already taken it you can revisit your results like this:

Locate the My Profile link at the upper left of any forums page. Your page may not look exactly the same as this picture but the link itself hasn't changed:

Click it and it'll take you to a page titled "User Control Panel". In the left (Your Control Panel) column, scroll down to the Your Quizzes section and click on the View Sanity Score link.

We also have a forum, The Sanity Score, where you can discuss your test results.