I saw this test on marko's blog. It's a shorter version of the Myers-Briggs test. Looks like I'm an INTP.
"INTPs are relatively easy-going and amenable to most anything until their principles are violated, about which they may become outspoken and inflexible. They prefer to return, however, to a reserved albeit benign ambiance, not wishing to make spectacles of themselves.
INTPs contribute a logical, system-building approach to their work. They like being the architect of a plan, because of the scheming and thinking involved, far more than being the implementer of that plan. Implementation tends to be drudgery. They are content to sit back and think about what might work, given their view of the situation. INTPs may ignore standard operating procedures. The hours that they spend are not what is important to them, but rather the completion of their thought process."
I'm always amazed at how closely these things can peg you. I think I'm probably a little more extraverted than this would indicate, though.