"Why are you adding cactus to our salad?"
"I heard that cactus stores water in its stem. So I decided to add cactus to make a mouth watering salad."
Where did Marco Polo die?
At the deep end of the pool.
During a long road trip, what did the zombie son ask his zombie father from the back seat of their car?
"Hey dad, are we dead yet?"
A professor was at a party and became indignant when asked if college professors were absent-minded.
"Professors haven't got bad memory," he declared. "They're not absent-minded. Don't you think I know where I am right now, and don't you think tomorrow I'll know where I was today? Would somebody like to ask me another question?"
"Yes," said another guest. "Is it true that professors are absent-minded and have bad memory?"
"Good!" said the professor. "I knew sooner or later somebody would ask me that question."