Question: A town only has one barber (he is male). The barber only shaves all of the people who do not shave themselves.
So who shaves the barber?
Answer: It's a paradox, if he shaves himself then the second sentence would be false because he only shaves those who do not shave themselves. If he does not shave himself, then according to the second statement he must shave himself.
Question: A rich man suddenly dies from a cut on his finger. The next day, two men appeared and claimed to be his long-lost son. They both fit the description in the will and had all the necessary documents. The family attorney proposed a blood test. One man agreed while the other point blank refused. The one who agreed was arrested for fraud at once. The second man was accepted as the heir. Why?
Answer: He was a hemophiliac, like his father, who died from a small cut. The blood test would kill him.