Good Riddles

Question: I'm fat and I'm round and I cause much joy, I'm often a dogs favorite toy. What am I?

Question: You wear me every day but you never put me on.
I will change colors if you leave me out too long.

What am I?

Question: There are 3 switches downstairs, each corresponding to one of the light bulbs upstairs. How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?

Question: After looking for his long lost brother that he has never met before, Justin is able to learn his brother's home address and name. When he shows up at his house he finds a fireman, a police man, and a mechanic watching television. He immediately hugs his brother.

How does he know which one is his brother?

Question: You have an 8 by 8 chess board that has two corner squares diagonal from each other removed. Is there any way to place 31 dominoes of size 2x1 to cover the remaining 62 spaces?