It was for an electronics degree course, not a job, and was aimed at seeing if I could think on my feet:
You have a plastic sphere. A hole is bored right through the middle of the sphere. The hole is 4 cm long. What is the volume of plastic remaining?
I needed one hint and then came up with the correct answer (a number times pi). I didn't try to do the multiplication by pi in my head! I subsequently used the question when interviewing a candidate for a software development job. The candidate not only had no idea how to tackle the question; he didn't even understand the solution when I explained it to him. He was not suitable for the job.
A question I was asked during a job interwiew was "What car do you drive?" When I replied "A Toyota Corolla", the interviewer said "Isn't that what taxi drivers in Luton drive?" I replied "It could well be" and made no further comment.
The same interviewer asked "Where do you see yourself 5 years from now?" I replied "Still doing the job rather than moving into Sales or Management but having more say in decisions affecting my work." I thought this showed sufficient ambition without threatening the existing management structure. I got the job but was laid off 7 years later, and then 6 months on was asked to come back!