What's wrong with OKCupid's matching algorithm.
Minor point, but if you are using factual questions to filter out stupid people, asking for the "right" number of continents is probably not ideal. You (and I) might disagree with someone counting Eurasia (or North and South America) as a single continent, but it is not really an indicator of stupidity in the way that believing in astrology or thinking the earth is larger than the sun are.According to the wikipedia article on continents, different models are taught in different countries, so you probably end up selecting for a different attribute than you thought.