Teacher: "Kids, what does the chicken give you?"
Student: "Meat!"
Teacher: "Very good! Now what does the pig give you?"
Student: "Bacon!"
Teacher: "Great! And what does the fat cow give you?"
Student: "Homework!"

LOL funny I have on too:

Teacher: Could you please pay a little attention here?
Student: Yes mam, I am paying as little attention as I can.