What am I? (Things)
The "invention" that allows you to see through walls
What is a window?
It appears once in a minute, twice in a moment, but never in a billion years
What number do you get when you multiply all of the digits on a cellphone?
0
When you multiply any real number by 0, the result is always 0
It can go up but not down
What is your age?
You have two coins that sum to 30 cents. One of them isn't a quarter. What are the two coins?
One of them isn't a quarter; that's the nickel. The other coin is the quarter.
The homeless have it, the wealthy need it, and if you eat it, you die
P.S. Kathryn, you are not allowed to respond to this one. Also, you cannot consider this plagiarism since I have your name 21 words before the number 21.
What is nothing?
You board a plane and notice that there isn't a single person on board. How can this be?
All of the passengers were married
It runs but never walks, often murmurs, but never talks, has a bed but never sleeps, has a mouth but never eats
What is a river?