Fun Riddles

Question: A grandfather has a broken grandfather clock that is off by a minute every hour (too fast). He figures out a way, while keeping it running at the same rate, to make the clock say the correct time twice a day.

How could he do this?

Question: What does a man do only once in his lifetime, but women do once a year after they are 29?

Question: What can one not keep, two hold, and three destroy?

Question: Four cars come to a four way stop, all coming from a different direction. They can't decide who got there first, so they all go forward at the same time. They do not crash into each other, but all four cars go. How is this possible?

Question: You put me in hard.
But then I become soft.
Blow me hard and I will get bigger.

What am I?