We usually then answer that question with a clever innuendo, followed by a clarifying punch line.
But really, who is there?
What are you waking up for every morning? Think about your life as if someone is knocking on the door of your motivations, your passions, your purpose. Who, or what, are you getting up, walking across the room, and opening the door for?
We have to answer much more complex questions than this every day. But not many are more important.
The even simpler question, is why?