Here’s a good one from Paul’s weekly jokes.
Two farmers, Jim and Bob, are sitting at their favorite bar, drinking beer. Jim turns to Bob and says, "You know, I’m tired of going through life without an education. Tomorrow I think I’ll go to the Community College and sign up for some classes."
Bob thinks it’s a good idea, and the two leave. The next day, Jim goes down to the college and meets the Dean of Admissions, who signs him up for the four basic classes: Math, English, history, and Logic.
"Logic?" Jim says. "What’s that?" The dean says, "I’ll show you. Do you own a weed-eater?"
"Yeah." "Then logically speaking, because you own a weed-eater, I think that you would have a yard."
"That’s true, I do have a yard."
"I’m not done," the dean says "Because you have a yard, I think logically that you would have a house."
"Yes, I do have a house"
"And because you have a house, I think that you might logically have a family."
"I have a family."
"I’m not done yet. Because you have a family, then logically you must have a wife."
"Yes, I do have a wife."
"And because you have a wife, then logic tells me you must be a heterosexual."
"I am a heterosexual. That’s amazing; you were able to find out all of that because I have a weed-eater."
Excited to take the class now, Jim shakes the Dean’s hand and leaves to go meet Bob at the bar. He tells Bob about his classes, how he is signed up for Math, English, History, and Logic.
"Logic?" Bob says, "What’s that?"
Jim says, "I’ll show you. Do you have a weed-eater?"
"Then you’re a queer!"