According to this site maintained by Dr. Martin Seligman, you can “develop insights into yourself and the world around you through these scientifically tested questionnaires, surveys, and scales.”
I took a few of these tests (some only a few minutes) and might have learned a thing or two.
The site has almost 400,000 registered users around the world. Use of the website is free–all you need to do is fill out a quick registration.