One good, clean joke is: "What do you get from a pampered cow? Spoiled milk." Another clean and wholesome joke is: "What is the difference between a school teacher and a train? A teacher says spit your gum out while the train says 'chew chew chew'."
Another clean joke involves an engineer, a doctor and a priest playing a round of golf. Ahead of them, another group of people plays so slowly and with such ineptitude that the three frustrated men go to the greenskeeper for an explanation. The greenskeeper tells them, "Those are blind firefighters. They lost their sight while saving our clubhouse last year, so they play for free whenever they want." The priest then says, "I will pray for them tonight." The doctor says, "I will ask my ophthalmologist if anything can be done for them." Finally, the engineer says, "Why can't they just play at night?"
One more clean joke goes: "One morning a policeman knocked on my door, but I locked it and ignored him in silence. He knocked again soon thereafter, but still I refused to open the door. The knocks grew louder and more frequent, but the cop would not leave. Finally, he peeked through the window and said, 'Sir, do you take me for an idiot? I can clearly see you in there. Open up!' I said, 'You can't come in, pal!' He responded, 'I don't want to come in, I just want you to step out of the car'."