What does an Island and the letter T have in common?

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

One night, a woman receives a call from the police. They tell her that her husband was murdered and that she should come to the crime scene as soon as possible. The woman drops the phone, shocked, and drives 20 minutes to the crime scene. As soon as she reaches the crime scene, the police arrest her and she is convicted of murder. How do the police know she committed the crime?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

How can you drop a raw egg from a height onto a concrete floor without cracking it?

In a football game, Christina defeated Teresa by 2 - 0 but no man from either side scored. How can this be possible?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

Do You See It?

Take one out and scratch my head, I am now black but once was red. What am I?