Hey computer, tell me a joke: the problem of teaching AI humour

Have you heard the one about a robot who walks into a bar? "What can I get you?" asks the bartender. "I need something to loosen me up," says the robot. So the bartender serves him a screwdriver. I'll bet you wouldn't have guessed that a computer wrote it – @jokingcomputer. Here's another one told by a computer: So how does Artificial Intelligence (AI) do when it comes to that most human of storytelling activities-- telling jokes?