A method of inconveniencing someone, usually a friend, by making them curious about something. When they ask for more information by using the word "what", the other person responds "hi", in order to give them no information at all.
Did you hear what Jimmy did before?
Hi. (Thus ends the "What? Hi.)
In a math test, when given information about a car traveling a certain distance, and using a certain amount of gasoline, you are shown four graphs and must pick one. One of the wrong answers is the miracle car, which gets more gasoline the further it travels. When a person picks this answer, they feel like a moron when they find out it's wrong.
Person A: "What did you get on the math test"
Person B: "I got a 94, i was off by one question"
Person A: "What question was it?"
Person B: "Number 12, I picked the miracle car, and boy do I feel stupid!