There are a whole bunch of those jokes. I learned them in Boy Scouts years back, as they were performed as skits. They were originally "Polish" jokes, but we changed them to West Virginians and Pennsylvanians (We're from PA, so we didn't mean offense to people). I found a few that we used to do (I removed any insulting references):
1. These two men rent a boat and go fishing in a lake. They are amazed at the number of fish that they caught that day, so one says to the other, "We'll have to come back here tomorrow!" The other asks, "But how will we remember where this spot is?"
The first guy then takes a can of spray paint, paints an X on the bottom of the boat, and says, "We'll just look for this X tomorrow." The other guy says, "You idiot! How do you know we'll get the same boat?"
2. These two men are building a house. One of them is putting on the siding. He picks up a nail, hammers it in. Picks up another nail, throws it away. Picks up a nail, hammers it in. Picks up another, throws it away.
This goes on for a while, and finally his friend comes over and asks him why he is throwing half of the nails away. He replies, "Those ones were pointed on the wrong end." The buddy gets exasperated and says "You idiot, those are for the other side of the house!"
I always enjoyed those jokes.