Try solving these before rushing to look at the answers.

1. The Elder Twin.  One day Kerry celebrated her birthday. Two days later her older twin brother, Terry, celebrated his birthday. How come?
2. Manhole Covers.  Why is it better to have round manhole covers than square ones?  (supposedly used by a very well-known software company as an interview question for prospective employees)
3. The 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?
4. Heaven.  A man died and went to Heaven. There were thousands of other people there. They were all naked and all looked as they did at the age of 21. He looked around to see if there was anyone he recognised. He saw a couple and he knew immediately that they were Adam and Eve. How did he know?
5. 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?
6. The Two Barbers.  A traveller came to a small town. He had never visited it before, he knew no one there and he knew nothing about the town or its inhabitants. He needed a haircut. There happened to be two barber shops close to each other on the main thoroughfare - the only barber shops in town. The man studied each of them with care. One shop was very neat and tidy. Everything about it was smart. The barber was sweeping away the last traces of hair from the floor while waiting for his next customer. The other barbers shop was very untidy. Everything looked rather run down and ramshackle. The scruffy-looking barber within was lolling on a chair waiting for his next customer. Both shops charged the same amount for a haircut. After careful consideration the traveller decided to go to the scruffy barber for his haircut. Why?
7. The Man in the Bar.  A man walks into a bar and asks the barman for a glass of water. The barman pulls out a gun and points it at the man. The man says 'Thank you' and walks out. Why?