How would you weigh an elephant without using a scale?

One sure-fire way to cherry-pick the juiciest applicants in any field is to prune the bush of potentials with the razor-sharp shears of a mind-bending riddle or trick question. The tradition of using logic puzzles in interviews has been taken to the extreme in companies such as Google, Hewlett-Packard, and Amazon.  However, we have to question the logic of this - candidates will surely search Google for advice on solving Google interview questions, won't they?

Apparently though, Google does encourage it's interviewers to ask more open-ended questions of its candidates, weeding out the inappropriate people by making assertions on their character and strategic thinking by analysing their answers.  Seems that Google interview questions have gotten out onto the web after all (Note to reader: here is a Google search result for this query
A recruitment agency in the UK carried out a survey of their candidates and found that "two out of three candidates welcome obscure lines of questioning as part of the job interview process." Even if questions seem unrelated to the job that a candidate is interviewing for, it may give them the opportunity to showcase their abstract thinking or personality, differentiating them from other candidates with similar profiles. Imagine you enter an interview situation at a major corporate and the HR manager who is interviewing you says: "Just entertain me for 5 minutes, I'm not going to talk".  Sounds like a great way to get through the day for the HR manager, but does it work?  What if a highly skilled candidate is shy or simply boring?

Would Mahatma Gandhi have made a good software engineer? This question was asked at Deloitte in 2011.  One person said "No.  Even if he developed the abilities nobody would be ready to employ him since most people believed he a) always spoke the truth, b) had no ill-will towards anyone, c) accepted his mistakes in public, and d) was very disciplined and hard-working".  Another said "No. The man never touched a computer in his life." And finally, another said "Yes, because he was a lawyer, so he had the ability to learn, the ability to retain and prove his knowledge academically (tests, bar exam) and practically (court, in dealings with the British). He was an innate problem solver, extremely persistent and good with people."
We believe that the 'when' and the 'why' of asking such questions would need to be well thought through for fear of losing a great candidate or selecting the wrong one.  The timing issue is imperative. Throw a candidate off at the start of the interview and he may lose confidence.  The 'why' is even more important.  Why would a particular problem demonstrate a candidate’s suitability for to a particular position? It's important to know what is being tested- ability to deal with stress, people-skills, logic or math aptitude? Despite these risks, a well-timed, quirky question could tell you at least some things about a potential new employee that more traditional questions wouldn’t reveal.
Watch this  video and see if you are smart enough to work at Google.