Answer:
Could be described as the cranium's version of snow.
What do you call a bad interior decorator?
Arnold Schwarzenegger has a big one, Michael J Fox has a small one, Madonna doesn't have one, The pope has one but he never uses it, Bill Clinton has one and he uses it all the time! What is it?
What can never be eaten at Thanksgiving dinner?
What kind of tree can you carry in your hand?
You throw me out when you use me and take me in when you are done.