Mrs. Smith needed to have her piano tuned so she asked a friend for a recommendation. She then made an appointment with the piano tuner, Mr. Opperknockity. He arrived two days later, tuned the piano satisfactorily, and left.
Shortly after that, Mrs. Smith noticed that the piano was terribly out of tune again. She called the tuner to complain about it and to ask for a return visit to solve the problem.
However, the tuner replied, "I'm sorry ma'am, but Opperknockity only tunes once!"
A heavily bandaged man was sitting up in bed at the hospital when his friend came to visit. "What happened to you?" the friend asked.
"Well, we went to the amusement park and decided to ride the roller coaster. As we came to the top of the highest loop, I noticed a sign by the side of the track. I tried to read it, but it was very small and I couldn't make it out. I was so curious that I went around again, but we went by so quickly that I still couldn't see what the sign said. By now I was determined, so I went around a third time. As we reached the top I stood up in the car to get a better view."
"And did you manage to see what the sign said this time?" asked his friend.
"Yes, it said remain seated at all times."