Good Riddles

Question: You wait for it. It cracks, stays for a moment, and then vanishes before your eyes. What is it?

Question: Filled with garb,
the price is free.
Just return what you don't need.

What am I?

Question: If you have a cake, how many pieces of cake can you form with 3 straight cuts?

Question: Hold me by the neck and I won't mind,
if I get wrong I just need a good wind.
If you want me you better pick wisely,
just use your ears and I'll follow you blindly.

What am I?

Question: Two children are born in the same hospital, on the same year, on the same day, and have the same father and mother. But they are not twins.

How is this possible?