Funny Riddles

Question: No matter how much rain comes down on it it won't get any wetter.

What is it?

Question: When do you go at red, but stop at green?

Question: Why don't mountains catch colds?

Question: The first is a sign of something good,
the second says whereto;
the third is vulgar and mean,
the fourth is bound by a ring;
the fifth is the noble one.
Together they all drum.

What are they?

Question: It turns into a different story.

What is it?