OK, yes, I confess: I like to do on-line tests that tell me what I should already know. I complete the quizzes in the hope that they'll provide me with the secret of happiness. All they can tell me, of course, is what I think other people think about me. From time to time, though, I find something useful, like Martin Seligman's Signature Strengths quiz. (The site has long list of other tests, too.)
I linked to it via an interview with Seligman on the Edge site. He argues that psychology has done a great job making people less miserable over the last 50 years by finding effective treatments for 14 major mental illnesses. However, it hasn't done much yet to help people be happier; that what his current research and his book Authentic Happiness is about.
The Seligman test gave me my five "strengths" - while fundamentally not a surprise, it was revealing to see character traits I know well represented as strengths and not as weaknesses. Seligman argues that playing to one's strengths gives you a better chance of getting to a Csikszentmihalyi flow state. I've been trying to figure out how to do this for years, and I was glad to get a hint.