There is a land where every inhabitant is either a day-knight or a night-knight. Day-knights tell the truth in the day and lie at night. Night-knights lie in the day and tell the truth at night.
Three inhabitants A, B and C are currently engaged in a conversation. A visitor approaches the three inhabitants and ask each of them their types. They say:
A: If asked, B would claim it is morning.
B: If asked, C would claim it is morning.
C: If asked, A would claim it is night.
Is it day or night? What is the type of each of the inhabitants?
A Jewish doctor gets a notice that due to his significant contributions to the field of medicine the Queen of England has decided to knight him.
He arrives for the ceremony and is instructed on the protocol. "Here's a paper with a Latin saying you'll need to memorize. When your name is called, you walk down the aisle and kneel. Then you recite the Latin phrase. The Queen will take her sword, touch you with the tip on the right shoulder, raise it over your head and touch your left shoulder, then over your head again and she'll touch your right shoulder. Then she'll say, "Arise, Sir Weinstein." Don't speak to her until she speaks to you."
The day of the big celebration comes. Weinstein has memorized the Latin saying.
After few candidates were "knighted"- they call his name and his heart starts pounding in his chest. He walks down the aisle, kneels down … and his mind goes completely blank.
A blackout! He just can't remember the Latin. The Queen is looking down at him, waiting, which only makes him more nervous.
Finally, in desperation, he blurts out the first thing he can think of in a foreign language: Ma nishtanah halaila hazeh mikol haleilot?*
Confused, the Queen turns to her Protocol Officer and says, "Why is this knight different from all other knights?"
*The opening question of the Jewish Seder ( Pesach festive dinner): Why is this night different from all other nights?
In Hebrew: מה נשתנה הלילה הזה מכל הלילות