Let it be simple and as direct as possible.

Interviewer : Tell me how much time (in days) and money would you require to clean all the glasses of each and every building (which is obviously composed of glasses) of New York City including all the glasses at the top as well as at the bottom of all buildings. Also mention the calculations for your contract and the money you would mostly prefer to accomplish this task. Most importantly you and only you have to do this job (i.e. you can’t ask anyone else to clean the glasses for you). You can even separately mention the costing of cleaning the window glasses and fixed glasses from both the sides (i.e. from inside as well as outside.)

* Time allotted for the question (to think and analyse) is half-an-hour.
** This was the most tricky, diplomatic and mind-manipulating question asked at one of the interviews conducted by Google for a highly paid job.