Good Riddles

Question: Man walks into a store and says to the shop owner: “I will spend $10 in your store if you double the amount of money I now have in my pocket.” Store owner agrees; doubles his money; he spends $10 and leaves. He repeats this at 2 more stores. When he leaves the 3rd store he has $0 dollars. How much money did he have in his pocket when he walked into the first store?

Question: What is as big as an elephant but weighs nothing?

Question: What room does a ghost not need?

Question: What's a horse's favorite sport?

Question: What goes round the house and in the house but never touches the house?