I have this toy that guesses what you are thinking of based on twenty questions that it asks you. It asks questions that seem to have nothing to do with the thing you are thinking of, and yet it gets it EVERY FUCKING TIME!
Well hold on! because the company has a web-based one as well.
http://www.20q.net
Try it out and post your results in this thread so we can see it's success rate and if there's a pattern to the logic.
Have fun.