Here's a particularly painful one:
There were two scientists, one from Russia and one from the Czech Republic, who were interested in studying bears in their natural environments. They had been camped out in the woods for a few days doing their research, but one night they mysteriously disappeared. When the rangers went to investigate, they discovered two well-fed bears, one female and one male, near the scientists' campsite. The rangers decided that they needed to kill the bears and see what was inside their stomachs. So they killed the female bear, and sure enough, the remains of the Russian scientist were inside her stomach. One ranger turns to the other and says, "you realize what this means, right?"
"Yes..." the other ranger says. "It means the Czech is in the male."