'All jokes are about shattering assumptions," says San Francisco Comedy College founder Kurtis Matthews. "Horror has the same structure of comedy, but the result or surprise [horror hopes to achieve] is fear, pain, or confusion." To give an example of the structural similarities between horror and comedy, Matthews says, "If you go home tonight, and you walk into your bathroom and there's somebody you don't know in your shower with a knife, the reason that's not funny is because it creates fear of pain, 'Is this gonna hurt?,' and confusion, 'What's going on?' Whereas if you walk into the shower tonight, and someone you know and love and trust is there, and they're covered in whipped cream, maybe playing a kazoo, you're going to laugh because there's no fear of pain."

On Friday, July 7, Matthews will appear at the San Diego Comedy Co-op to discuss technical aspects of comedy in an introductory workshop for aspiring comedians. In the workshop, Matthews will discuss the Joke Diagram, a schematic structure of jokes.

"Anywhere that we laugh, we have an assumption that is unspoken. Harpo Marx would open his overcoat, and you'd have an assumption of what goes underneath an overcoat. But out of the overcoat comes a lion, or his brothers, or a table setting -- it's the same freakin' joke, and people laugh at it over and over."

According to Matthews, every joke has two stories. "The first story can be assumed. The second story is the reinterpretation." For his course, Matthews uses the text Step by Step to Stand-Up Comedy by Greg Dean. In this book, Dean explains the difference between a "setup" and a "first story": "As the first part of the joke, the setup is the words and/or actions used to get the audience to expect something...then, based on the setup, the first story is the detailed scene imagined by the audience of what they expect to be true."

Dean continues, "Let me illustrate with an old, standard joke: 'For 40 years I've been married and in love with the same woman. If my wife ever finds out she'll kill me.' When the comic says, 'For 40 years I've been married and in love with the same woman,' that -- and only that -- is the setup. Then, from hearing this setup, the audience imagines a much more elaborate first story." The first story may vary because it is created in an individual's mind, but most people might think, "Here is a man bragging about his wife," only to find out he is cheating on his wife and bragging about his mistress.

In the first chapter of his book, Dean explains, "In order to work, a joke has to surprise you. The trick is that you cannot be surprised unless you're expecting something else first." He gives a joke by Steve Martin as an example: "Sex is one of the most beautiful, wholesome, and natural things...that money can buy."

"If you do not have one thing that can be perceived in two different ways, you do not have a joke," says Matthews. "If I say, 'I got on the bus the other day, and there was this crazy person picking fleas off of their head and calling me a wombat,' I have only created one story; you only have one image in your head. I haven't shattered any of your assumptions. 'Crazy person, big deal.' If I add a second story, like 'I can't believe he was the mayor,' that shatters your assumption because I went from 'crazy guy' to 'person of responsibility.'"

Matthews cites Zsa Zsa Gabor's famous quip, "I'm an excellent housekeeper -- every time I get divorced I keep the house," as a good example of a shattered assumption because the word "housekeeper" is assumed to mean one thing but is reinterpreted to mean something else that is unexpected. Another example is a one-liner by Bob Smith, who said, "My Aunt Lorraine said, 'Bob, you're gay. Are you seeing a psychiatrist?' I said, 'No, I'm seeing a lieutenant in the Navy.'"

"I've met people who were crazy and kind of creepy, but I've yet to meet the person who couldn't be funny," says Matthews. "The funniest people are not the biggest and brightest, they're the ones who are the most imperfect. We laugh at imperfection."

Matthews insists that every person is, to some degree, a comedian. "We've all been at a party; we've all told stories that make people laugh. If you show the world a point of view that is different than theirs, they'll laugh at it. Iraq is not funny, but Jon Stewart said, 'Iraq is terrible, we all agree with that, but how else are we going to teach kids world geography?' The assumption is Iraq is bad. The reinterpretation is Iraq is good for this reason." -- Barbarella

Intro to Stand-Up Workshop Friday, July 7 6 p.m. to 8 p.m. Comedy Co-op 11211 Sorrento Valley Road, Suite M Sorrento Valley Cost: Free Info: 858-869-5687 or www.comedycoop.org