a bit complex thought for english language, but i''ll try...
i believe intelligence is one of most abused women on this planet. intelligence is a tool. it means how many GHz the main processor has. nothing less, nothing more.
intelligence can be measured when the tests are balanced to the environment where they are used. from the definition every country (culture, nation...) has the approximate iq 100. not less, not more. but you can have politics too, they say, so you can manipulate with numbers... sky is the limit.
and even if you want to measure whole world on one scale (which i agree is completely irelevant scale) there is a question of population which created data. in my country there is basically one test for everybody at 13. so we can have pretty good data. how many persons are tested in darfur?
intelligence has nothing with success, creativity, social adaptation or whatewer else. it's only the processor. and from there on you need to have a good software and good knowledge how to use it.
intelligent persons are equally distributed among rich and poor, educated and non educated, talented or non-talented, well, anyzhing you can imagine. opposite maybe common thinking it's even not very correlated to mental diseases...

and i believe there are no serious iq150 questions. education, knowledge, informations, analytical and synthetic skills and preferable at least similar philosophical attitude to many things in general is a way to a good answer that you could accept. if you trust in someone because of his/her intelligence, then, i think, you'll need a lot of faith.
i believe iq (measured in known environment) can be a relevant data if you have almost all others data. and this same iq data would be very meas leading without all other data.
charles, i found interesting your thought on connection between intelligence and language. it's very similar to my most reasonable (not original) thought that you cannot think without language. there are many who argues it's not true and por ejempio show music and visual art. well, doesn't change my mind. but i do believe there could be intelligence even without language. there had to be intelligence to start language, at first. and don't think that thinking and intelligence are not even really connected and of course not the same. don't even want to wright about intelligence and other creatures (beside hs) living on this planet. we are not that special, at least not in that way.
as intelligence can be quite useful, can be also a great burden. among many other things intelligence can be very helpful when someone wants to close his/her eyes and mind before the reallity. intelligent person knows it's intelligent. and because of that thinks that what he/she thinks is correct. it's true. sometimes.
einstein was genius and as such very intelligent. that's why i don't understand theory of relativity. but i'm a little intelligent too and so far i understand that there must be some relativity.