Can I ask a stupid question?

I used to go to Vivekanada Center of New York for Sunday-Service. Swmijee was fun to listen to; Vedanta sounded like New York times columns.
One of the joke he told was as follows:
There are two elderly man sitting in Central park and the conversation goes like this...
      Man One: How old area You?
      Man Two: Answered, How soon do you need to know?

We all laughed. However, Is it really Stupid question?

When talking we are only covering what we already know. Only way to learn what other person needs to know (or what we already don't know) is to ask (stupid) question - and than listen to the answer.

Have you listen to a child? Have you noticed how often they ask “why?” - all the time.
Our social conditioning kills that curious child within us; there are many reasons: fear of being judged is among them.

Question is Powerful; Question Demands Answer; Question Stimulate Thinking.

Very early in my career, I was working with Swiss Banker about a banking system automation. I spend a day talking to him about all complex processes the Bank does, but did not ask about how do the Bank's normal day-to-days operation. Being a neophyte, I was happy knowing that I am learning complex operations.
At the end of the day Banker asked, “Do you know the meaning of your job - Business Analysis?” He said smiling you did only “B” part of job and dropped the A out of it. And key tool for a is “Ask Question”.

On the same note open ended question is better than close ended question
   exempli gratia:
         Close ended question: Can I help you?
         Open ended question: How can I help you?
Observe how the second statement prompts the object to ask for specific help.

So don't be afraid to ask question - it indeed is powerful