Ever heard of the Myers-Briggs Type Indicator?

It's a very accurate measure of personality. Though it's obviously not 100%, it's the most accurate one I've ever seen. It's generally used in psychology studies, in psychotherapy, and the like. It measures 4 dimensions of your personality:

Introversion-Extroversion
Intuition-Sensing
Feeling-Thinking
Perceiving-Judging

And of course, there's an abridged version of it online.

Anyway, just for fun, take it and post your results! I got INFP, which stands for Introverted Intuitive Feeling Perceiving. A lot of it was right on the dot. There are many websites that go into a lot more depth about the results than the results of this test.

Test:
Myers-Briggs Type Indicator

More Detailed Result Descriptions:
Keirsey Temperament Website - Overview of the Four Temperaments