Good 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: A man named Edward was born on December 21st, yet his birthday is during the summer this year.

How could this be?

Question: You walk into a room with a rabbit holding a carrot, a pig eating slop, and a chimp holding a banana.Which animal in the room is the smartest?

Question: Is an older one-hundred dollar bill worth more than a newer one?

Question: Using 3 periods (.) and 1 question mark (?) make this a logical and grammatically correct sentence:

"That that is is that that is not is not is that it it is"