What flies without wings?
What can always be measured but never can be seen?
What treat is never on time?
What time is it when the clock strikes 0?
If it takes eight men ten hours to build a wall, how long would it take four men?
Every time you lose something, you always find it in the very last place you would look. Why is this?
There is a puzzle which can be asked all day with a different correct answer each time. What is the puzzle?