Logic Riddles

Question: I have existed for centuries, but last only a month. What am I?

Question: Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

Question: What is 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 10,000?

Question: A group of ten people are going out for pizza but only two of them have an umbrella to keep them dry. But they manage to walk all the way to the pizza place without getting wet.

How is this possible?

Question: There was a man who was born before his father, killed his mother, and married his sister. Yet there was nothing wrong with what he had done.

Why?