Pax usually find a map in their lap pretty quickly!

Q: "How much does it cost to learn to fly?"
A: "More than you ever make while flying for a living...bad decision for me heh?!"
Q: "What is the landing like compared to a commercial flight?"
A: "You tell me in 5 min"
Q: "Are we all going to fit in that little thing?"
A: "We may be pretty full, do you mind waiting here for the next plane?" (Charter out of small alpine lake, many miles from civilization)
Q: "What does that red lever do?"
A: "Ejects all the passengers." (Usually grab the mixture, stare at the pax, then pull hand quickly without actually pulling the mixture)
Pax: "So how long do you have to fly these cute planes before you can fly commercially?
Me: "Did you pay for this flight?" (Acting very sincere)
Pax: "Yes"
Me: Sit quietly staring ahead
...it's endless...just when you thought you heard the dumbest question, someone comes up with the trump card!