What always comes into a house through the keyhole?

Can you find the ages of a son, father and grandfather based on the following facts?
The sum of the ages of grandfather, father and son is 140 years.
The age of the son in months is the same as the grandfather in years.
The age of the son in days is the same as the father in weeks.

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Before Mount Everest was discovered, what was the highest mountain in the world?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

They are the five precious gems of an everyday sort and all can be found on a Tennis Court. Who are they?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

John speaks the truth only once a day in a week. Below are a few hints for you:

First: Days are Sunday, Monday and so on.
Second: One day he says, "I lie on Monday and Tuesday".
Third: On the next day, he says, "Today is either Thursday, Saturday or Sunday".
Fourth: On the next day, he says, "I lie on Wednesday and Friday".

Can you identify the day on which he speaks the truth?

A man was driving a black truck. His lights were not on. The moon was not out. A lady was crossing the street. How did the man see her?