Basically, I say 'What would you do if.." and then a scenario. The person below answers and asks "What would you do if.." again.

Starting I say..
What would you do if you and your whole family got together for christmas (including any people you hate, never met, are in prison etc. not including dead people) and suddenly someone looked out of the window and shouted "THERE'S A BIG BOMB COMING TOWARDS US!!!" So everyone crowds to the window and there is really a bomb heading towards the house, from the sky.