Good Riddles

Question: There are two sisters: one gives birth to the other and she, in turn, gives birth to the first. Who are the two sisters?

Question: What goes up with the intention of falling down?

Question: Mr. Smith has two children. If the older child is a boy, what are the odds that the other child is also a boy?

Question: When is homework not homework?

Question: Skinny I am fast,
fat I am slow,
but I'll still delight you from your eyes to your nose.

What am I?