NSFW
I got hardcore porn, we both chose it as the best and won!
This idea has been done by many others, from converting books, capatchas, image recognition and tagging.
The most original aspect is getting a match with another player a few times gives you more and more points, so people will try to guess what is the most common response. Also it asks for like or not like for some pictures instead of asking for tags or to trace an outline which should give interesting results about how people think.