It
The maker doesn't buy it. The buyer doesn't use it. The user doesn't see it. What is "it"?

Geographical Nightmare
A train crash occurs exactly on the border between Mexico and the United States. Where do you bury the survivors?

Seeing the Light
You are in a room with no windows and one door. The door is closed. There are three switches on the wall. One of these switches controls a light that is found in an adjacent room. How do you figure out which switch controls the light if you are only allowed to open the door and exit the room you are in once?

Alfabetical Antangonizer
What letter comes next?

A, H, I, M....

Thinking Outside the Box
Can you connect all of the following dots using only four straight lines? (The beginning of one line must start at the end of another.)

. . .
. . .
. . .

Calculus Common Sense
Two young children are digging a hole in a sandbox. They dig in the area confined by the lines y = x, y = -x and y = -5 and are able to increase the depth of the hole at a rate of dh/dt = 1 meter every 30 minutes. Keeping in mind that dh/dt is a negative, write a function f(t) that defines the amount of dirt in the hole at any given moment.