A number of people have broken the sound barrier, either in a super-fast car, or in nice fancy planes. However, hundreds of years ago it was broken on horseback. How?

Many people who ride horses carry whips. They crack the whip while they ride the horse. When a whip is cracked, the tip travels faster than the speed of sound, which makes the loud snap. It actually creates a miniature sonic boom of sorts. The whip breaks the sound barrier, thus, it was broken on horseback.

A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.
How can the swan succesfully escape?

Assume the radius of the lake is R feet. So the circumference of the lake is (2*pi*R). If the swan swims R/4 feet, (or, put another way, 0.25R feet) straight away from the center of the lake, and then begins swimming in a circle around the center, then it will be able to swim around this circle in the exact same amount of time as the monster will be able to run around the lake's shore (since this inner circle's circumference is 2*pi*(R/4), which is exactly 4 times shorter than the shore's circumference).
From this point, the swan can move a millimeter inward toward the lake's center, and begin swimming around the center in a circle from this distance. It is now going around a very slightly smaller circle than it was a moment ago, and thus will be able to swim around this circle FASTER than the monster can run around the shore.
The swan can keep swimming around this way, pulling further away each second, until finally it is on the opposite side of its inner circle from where the monster is on the shore. At this point, the swan aims directly toward the closest shore and begins swimming that way. At this point, the swan has to swim [0.75R feet + 1 millimeter] to get to shore. Meanwhile, the monster will have to run R*pi feet (half the circumference of the lake) to get to where the swan is headed.
The monster runs four times as fast as the swan, but you can see that it has more than four times as far to run:
[0.75R feet + 1 millimeter] * 4 < R*pi
[This math could actually be incorrect if R were very very small, but in that case we could just say the swan swam inward even less than a millimeter, and make the math work out correctly.]
Because the swan has less than a fourth of the distance to travel as the monster, it will reach the shore before the monster reaches where it is and successfully escape.

In the land of Brainopia, there are three races of people: Mikkos, who tell the truth all the time, Kikkos, who always tell lies, and Zikkos, who tell alternate false and true statements, in which the order is not known (i.e. true, false, true or false, true, false). When interviewing three Brainopians, a foreigner received the following statements:
Person 1:
I am a Mikko.
Person 2:
I am a Kikko.
Person 3:
a. They are both lying.
b. I am a Zikko.
Can you help the very confused foreigner determine who is who, assuming each person represents a different race?

Person 1 is a Miko.
Person 2 is a Ziko.
Person 3 is a Kikko.

Two men are in a desert. They're both wearing backpacks. One of the men is dead. The man who is alive, has his pack open. The dead man's pack is closed. What is in their packs?

It's 7:00 am. You are asleep and there is a sudden knock on the door.
Behind the door are your parents, who came to have breakfast.
In your fridge: bread, pasteurised milk, juice, and a jar of jam.
What will you open first?

What do the letter 'T' and an island have in common?

They are both in the middle of water. The letter 't' is in the middle of the word 'water' and an island is surrounded by water, therefore, in the middle of water.

Shadow drove into the Speedy Service Station and pulled up to the pumps. "Fill it up, please," said Shadow. "
This may sound strange," said the owner, "but I'd rather fill two cars from out of town than one car from this town."
Shadow looked across the small town and replied, "I know just what you mean."
Why would the owner feel this way?

The owner would rather fill two cars from anywhere than one car from town because he would make twice the amount of money.