Interesting Riddles I Found Today

Some extreme (some might say) riddles I got today, here are some of them:

1. What room has no walls, no windows, and no doors?

2. What is closed when open, open when closed, and never open or closed?

3.
A boy was at a carnival and went to a booth where a man said to the boy, "If I write your exact weight on this piece of paper then you have to give me $50, but if I cannot, I will pay you $50."

The boy looked around and saw no scale so he agrees, thinking no matter what the carny writes he'll just say he weighs more or less.

In the end the boy ended up paying the man $50. How did the man win the bet?

4.
A prisoner is sent into custody. He is soon in court in front of the judge. The judge says, "I will give you one chance to lessen your punishment. To do this, you have to say one statement. If that statement is true, you will be in jail for 4 years. If it is false, you will be in jail for 6 years."

After a day of endless thinking, the prisoner finally came up with something. The judge called the prisoner in to hear his statement. After stating, the prisoner was set free.

What did the prisoner say?

5.
Three men decided to split the cost of a hotel room. The hotel manager gave them a price of $30.

The men split the bill evenly, each paying $10, and went to their room. However, the hotel manager realized that it was a Wednesday night, which meant the hotel had a special: rooms were only $25. He had overcharged them $5!

He called the bellboy, gave him five one-dollar bills and told him to return it to the men.

When the bellboy explained the situation to the men, they were so pleased at the honesty of the establishment that they promptly tipped the bellboy $2 of the $5 he had returned and each kept $1 for himself.

So each of the three men ended up paying $9 (their original $10, minus $1 back) totaling $27, plus $2 for the bellboy makes $29.

Where did the extra dollar go?

Can you solve any of them?