After too many months on the range, a young cowboy comes into town looking for some female companionship.
The bartender at the saloon breaks the bad news. "There ain't no women in this town."
The cowboy is aghast. "What do y'all do for sex?"
"Well," says the bartender, "if we get desperate enough, Old Man Thompson has a herd of pigs out at his place."
The cowboy stares at him in disgust.
"I'll never get that desperate," he says.
"That's what you say now," says the bartender, "but you'll change your mind."
As the cowboy gazes around the saloon, he sees all the men in the place nodding their heads in agreement.
"Never happen," he says, and stomps out the swinging doors.
When he returns to the town after his next stint on the range, though, six more womanless months have passed and the situation hasn't changed.
"Give the girls down at Old Man Thompson's a try," suggests the bartender. "Everyone else does."
"No way," says the cowboy.
Finally, though, the night before he's due to leave town for the range again, the cowboy breaks down and sneaks off to pay a visit to Old Man Thompson's. He returns to the saloon only to find the word has gotten out.
Beneath his ten-gallon hat, his face turns red.
"I thought you said all you guys do it," he says to the bartender.
"They do," said the bartender. He starts to chuckle, and the men in the bar burst into raucous laughter.
"Then what?" howls the cowboy.
"You picked the ugly one."
(There's a variation on this joke, where the barroom acts all freaked out when the cowboy returns, and the punchline is "You chose Black Bart's girl!")