You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

What goes up but never comes down?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

You have two strings whose only known property is that when you light one end of either string it takes exactly one hour to burn. The rate at which the strings will burn is completely random and each string is different.

How do you measure 45 minutes?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

The world's largest Thanksgiving turkey was on display at a fair. Everyone was admiring it when suddenly a woman ran up and shot the turkey and left. Everyone knew her yet nobody made any attempts to stop or report her. Why?

A sundial has the fewest moving parts of any timepiece. Which has the most?

Find the value of "a" by solving the maths equation in the picture below: