First I knw how noobish this is and how any other time it would probably be closed for being flame bait but I have a great idea that should be simple enough.
Port 20Q to the PSP(it is that thing that asks you 20 questions and can "read your mind") all it is a very complicated thesouraus(misspeled. Also incase you don'e know what that is, it is basicly a list of question in an order. If yes is answered than you go another question on the list, and if no is answered it goes to a different one. This way it eliminates every other possibility). Of course writing the thesaurous(is this the correct way, I am too lazy to use google) is really hard, but I am pretty sure it is posted somewhere. Once you find that it is just a lot of crunching "yes, go here. no go here. Continue in the order of the thesauros".
Anyway, if for some unexpected reason this is harder to do(with the exception of finding the list itself. That is the one biggest flaw, that and finding a programmer willing enough to do this, and of course with enough time)
As usual, don't flame me, I don't know anything about code, blah blah blah. Seriously, those 20Q things are frekin awsome, and theoretically this isn;t dificuilt to make, just time consuming, If I knew how(and thought I could make a good gui. Art was never my thing) I would do it.
Thanks, and remeber how awsome these things are.