Good Riddles

Question: In the harbor of a small town, there is a large boat. Coming off of the boat is a ladder reaching down so that the bottom rung is just above the surface of the water. As the tide comes in, the water rises at 1 foot every 30 minutes, and continues like this for 3 hours. If the rungs are each 1 foot apart, how many rungs are under water when the tide stops rising?

Question: Without me, nothing exists. What am I?

Question: What has a single eye but cannot see?

Question: I'm light as a feather, yet the strongest man can't hold me for more than 5 minutes. What am I?

Question: One evening a man started to run. Then he turned left. Soon after, he turned left again. Then he started running home. When he got home there were 2 masked men waiting for him. Who were they?