A word about Humor

Whenever you tell a joke there are couple of things you need to remember in order to make the joke a success:

1) Delievery: Always know when to start and when to end the joke. Know how to convey with your voice the high's and low's of the joke itself.

2) Realism: The more a story sounds real the funnier it is. That is what successful comedians use in their act. They always tell a story where they encounter an unusual situation where funny things can happen.

3) Be animated: When you tell a joke you might want to be animated with your hands and voice in order to describe something. It is far more effective to use your imagination and portraying it through your voice or through hand gestures. People would enjoy hearing about the joke more.

4) Poke fun at yourself: Don't take yourself too seriously. If you are tall/ short/fat/skinny/muscular, you can always find something funny about you that you know people will have a good laugh it. If you laugh at yourself people will be more comfortable around you.

For an example, watch this fat comedian:
http://www.youtube.com/watch?v=_cgitFqglm8

Good points. Very good points.
To take that further, another good trick is to subconsciously induce laughter. While saying something that's funny, look the person you're speaking to in the eyes and then slowly and every now and then just crack a small smile with your eyes and mouth, maybe gradually increasing that but not a lot. When you're looking someone in the eyes like that it asserts a certain subconscious dominance and the person is very likely to follow your lead. So the person will start cracking into a smile too.
Anyway, humor is basically having two conflicting feelings in your mind at one time. That's it. But they both have to be strong. That's why humor is, at its core (not talking about some advanced and obscure stuff like Andy Kaufman and Mitch Hedberg used) telling a story or setting up a belief and then quickly shattering it so that you put the story in a whole other context. And that's what punchlines are for. Oh, and over-exaggerate everything. Seriously.
Then like I said there's a series of additions to that like refering to very specific previous things that you said or exist, using completely nonsense humour, joining jokes, double punchlines and so on.
To use a nice example, watch this http://www.youtube.com/watch?v=0JdR-mQXwQU
There you have like a context of christ (peter) being expressly whipped and in an extreme state of submission, then all of a sudden the whole thing absurdly reverses from one extreme to the other with lots of exaggeration.

Bump

Below is an animated version of Dane Cook telling a joke about man getting hit by a car. There is a reason why chicks thinks he is funny (and why i think he is funny but also over-rated and his over exposure is due to large young female fans) because he keeps things simple, has a good delievery, good realism, and he is very animated.

http://www.youtube.com/watch?v=D7UqfP3FGYU&mode=related&search=