Living on a terrestrial ball

I never was, am always to be. No one ever saw me, nor ever will. And yet I am the confidence of all, To live and breath on this terrestrial ball. What am I?

Arvaus!

Tomorrow or the future.

The statement

A man was to be sentenced, and the judge told him, "You may make a statement. If it is true, I'll sentence you to four years in prison. If it is false, I'll sentence you to six years in prison." After the man made his statement, the judge decided to let him go free. What did the man say?

Arvaus!

He said, "You'll sentence me to six years in prison." If it was true, then the judge would have to make it false by sentencing him to four years. If it was false, then he would have to give him six years, which would make it true. Rather than contradict his own word, the judge set the man free.

Manhole Covers

Why is it better to have round manhole covers than square ones?

Arvaus!

A square manhole cover can be turned and dropped down the diagonal of the manhole. A round manhole cannot be dropped down the manhole. So for safety and practicality, all manhole covers should be round.

Swimmer in the Forest

Deep in the forest was found the body of a man who was wearing only swimming trunks, snorkel and facemask. The nearest lake was 8 miles away and the sea was 100 miles away. How had he died?

Arvaus!

During a forest fire, a fire-fighting plane had scooped up some water from the lake to drop on the fire. The plane had accidentally picked up the unfortunate swimmer.

Death in a Field

A man is lying dead in a field. Next to him there is an unopened package. There is no other creature in the field. How did he die?

Arvaus!

The man had jumped from a plane but his parachute had failed to open. It is the unopened package.
This is sometimes given with the following rather elegant clue - as he approached the center of the field he knew he was going to die.

Trouble with Sons

A woman had two sons who were born on the same hour of the same day of the same year. But they were not twins. How could this be so?

Arvaus!

They were two of a set of triplets (or quadruplets etc.)

The Elder Twin

One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How come?

Arvaus!

At the time she went into labor, the mother of the twins was travelling by boat. The older twin, Terry, was born first early on March 1st. The boat then crossed the International Date line (or any time zone line) and Kerry, the younger twin, was born on February the 28th. In a leap year the younger twin celebrates her birthday two days before her older brother.

The Broken Match

A man is found dead in a field. He is clutching a broken match. What happened?

Arvaus!

He and a number of other passengers were making a balloon trip in a desperate attempt to flee a country. The balloon had to lose weight to stop it from crashing. He drew the short match and had to jump.

Deadly Party

A man went to a party and drank some of the punch. He then left early. Everyone else at the party who drank the punch subsequently died of poisoning. Why did the man not die?

Arvaus!

The poison in the punch came from the ice cubes. When the man drank the punch the ice was fully frozen. Gradually it melted, poisoning the punch.

The Man who Hanged Himself

Not far from Madrid, there is a large wooden barn. The barn is completely empty except for a dead man hanging from the middle of the central rafter. The rope around his neck is ten feet long and his feet are three feet off the ground. The nearest wall is 20 feet away from the man. It is not possible to climb up the walls or along the rafters. The man hanged himself. How did he do it?

Arvaus!

He climbed on a block of ice which has since melted.
This one is often stated with the clue of a puddle of water.