The (probably) most famous personality test, the Myers-Briggs Type Indicator, testing whether one is:
Extraverted (E) or Introverted (I),
Sensing (S) or iNtuitive (N),
Thinking (T) or Feeling (F), and
Judging (J) or Perceiving (P).

I tested as INTP (Introverted iNtuitive Thinking Perceiving), but very close to ISTP (Introverted Sensing Thinking Perceiving).

The test can be found here.