Best riddles

The day before yesterday Cindy was 17. Next year she will be 20. How can this be?

What is it that has six legs, two heads, and flies?

A wealthy man lives alone in a small cottage. Being partially handicapped, he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?

I am a 5 letter word. Take away the first letter and I am a country's name. Take away the first two letters and I become the opposite of the 5 letter word. Who am I?

Four men were fishing in a boat on the lake. The boat turned over and all four men sank to the bottom of the lake. And yet, not one single man got wet. How is this possible?

Two girls ate dinner together. They both ordered iced tea. One girl drank them very fast and had finished five in the time it took the other to drink just one. The girl who drank one died while the other survived. All of the drinks were poisoned. How is that possible?

The more you have of it, the less you see. What is it?

If an electric train is going east at 60 miles an hour and there is a strong westerly wind, which way does the smoke from the train drift?

There was a railroad crossing without any cars and trucks! Can you spell that without using any "R"?

In a supermarket, the first 25 customers of the day purchased an average of two items each. After a further 15 customers, the average number of items purchased by each customer rose to eight. What was the average number of items purchased by the last 15 customers only?