Little Johnny and the fruit test.
One day teacher said to the class, "Class, we're going to play a name game! I'm going to hold something behind my back and give you some clues, and you have to guess what it is, okay?" "Okay teacher!" replied the class. "Okay class, I'm holding something behind my back that's a fruit and it has a thick yellow skin. Who knows what it is?" "Is it a banana?" asked Sally. "No, it's a lemon!" replied teacher with a smile. "But that was good, Sally. I like how you're thinking! Okay, now I'm holding something behind my back, it's kind of round, it's orange and you eat it. Can anyone guess what it is?" "Is it an orange, teacher?" asked Peter. "No Peter, it's a squash!" said teacher. "But that was a good try. I like how you're thinking!" Little Johnny raised his hand. "Yes, John?" asked teacher nervously. "So teacher, I have something in my pocket, and it's hard and it has a head. What is it?" "Johnny, that's disgusting!" shouted teacher. "It's a quarter, teach. But I like the way you're thinking."