Having been on both sides of the table on this one, the reaction to the odd and stereotypically lame questions can be more informative than the "good" ones.
The worst of that sort I was ever asked was if I would take a doughnut.
They had one on a plate on the table, but it was sitting in front of an empty chair next to the 4th coffee cup on the table (only three interviewers) giving the appearance that it was a 4th person's doughnut. The job dealt with a fair number of uncomfortable situations and they wanted to see how gracefully the interviewee could deal with it.
The one I later asked as an interviewer was to go 3rd in a team interview, and when it was my turn to ask I would put one of those aluminum briefcases that movies always show cash in on the table and ask the interviewee to name something inside. I actually carried the briefcase regularly so there was mostly normal things inside, but in dozens of interviews I only ever got two good answers: "air" which is almost impossible to be wrong, and "pencil" which we actually had to look to see because I couldn't remember (their wasn't). The point of this one was to see how quickly the person could deal with the random context change and how logically they approached the issue.
The point is that sometimes the answer itself doesn't matter in the least, the interviewer is interested in how you handle yourself or how you arrive at the answer.