Harvard has a pretty interesting little ongoing study. I first heard about this in one of my gender studies classes at Whitman because of course the topic came up about how strongly people held certain stereotypes even when they said the wouldn't judge people based on race/gender/whatever. The study uses a timed word/picture matching test to determine your automatic preferences and can be pretty informative about the stereotypes you may hold without even being aware of it.

They developed a test which you can take HERE to see which presidential candidate you implicitly prefer.

You can find out more about the psychology behind the tests and the idea behind implicit attitudes HERE.