I have no interest in politics whatsoever so I think that the politics one will definitely get a swerve.
I think music is good because you can always neg them about at least one artist that they like. Whether that's Justin Bieber, 1 Direction or another.
I'm tempted to head out one day, just get a string of random chats going and through different subjects in and see what the responses are. I could almost do a subtle poll as to what they do like and what they don't, if I use each subject say 10 times in an afternoon, if I can get that many approaches... then I can find out what really works well, which subjects are better for negs etc and take it from there.
I like the whole Cube thing and it reminds me of some of the games that have been played before with the imagination and simply asking them to answer non-specific questions which actually give you more information than they think they are giving you.