You need: A sharp mind.
How to play:
1) You can have as many participants as you want. All players can sit in a circular arrangement.
2) One of the players should think of some object, and without disclosing to the other members of the group what he is thinking about, he/she should address all of the others, asking them: "Guess what is my thought like?"
3) The first one addressed should, without having any idea as to what the leader has in mind, say, "Your thought is like a star". The second one may reply, "Like a bag". Every one who is asked must reply what they think the questioner's thought is like.
4) Now the questioner should ask the one who suggested that it was like a star why the object he thought of (example, a plane) was like a star. The one who has been asked must justify himself and give a reason why his fountain pen is like a star: "Your fountain pen is like a star because it can enlighten the world".
5) Then the next one must justify himself by saying something like: "The fountain pen is like a bag because it can express a bag of emotions". Thus, every one in the group must give the reason of his previous answer. This game requires quick thinking and initiative on the part of the participants.