A biologist, an artist and an engineer were discussing the merrits of wives vs. mistresses.

The biologist said, "Wives are better than mistresses because they provide a stable home environment that is conducive to raising healthy, well educated offspring. Without good wives all children would be indistinguishable from the animals."

The artist retorted, "Mistresses are better because they add spice to life and make you more creative. Without mistresses there would be no Mona Lisa or Sistine Chapel."

The engineer said, "You're both wrong. It's best to have a wife AND a mistress; that way each thinks you're spending all your time with the other but in reality you can go to the lab and get some work done."

This is fun! I have 7 at the moment... but here's just one for now (though you've probably heard it before):

An engineer was crossing the road one day, when a frog called out to him and
said, "If you kiss me I'll turn back into a beautiful princess"

He bent over, picked up the frog and put it in his pocket.

The frog spoke up again and said "If you kiss me I'll turn back into a
beautiful princess and stay with you for a week"

The engineer took the frog out of his pocket, smiled at it and returned it
to his pocket. The frog then cried out, "If you kiss me I'll turn back
into a beautiful princess and stay with you for a week and do ANYTHING you
want me to"

Again the engineer took the frog out of his pocket, smiled at it and
returned it to his pocket.

Finally the frog asked, "What's the matter? I've told you I'm a beautiful
princess and that I'll stay with you for a week and do ANYTHING you want me
to. Why won't you kiss me?"

The engineer said, "Look, I'm an engineer. I don't have time for a
girlfriend, but a talking frog, now that's cool"

I heard this from a math teacher:

A biologist, a engineer and mathematician vacation in Britain. They see a black sheep off in the distance.

The biologist says, "Ah! So the sheep in Britain are black!"

The engineer says, "No. At least one kind of sheep in Britain is black."

The mathematician says, "No. There is at least one sheep in Britain that is black on one side."

In 1493
Galileo Galilee
shocked the world
when he unfurled
the secret of the starry sea.

He was world renowned,
his theories sound.
But the Pope, wit slow
said he didn't know
his math from a scroll in the ground.

I love the "10 kinds of people" one. I've seen it on a T-shirt, which I covet. Here's another...

A priest, a doctor, and an engineer were waiting one morning behind a particularly slow group of golfers. The engineer fumed, "What's with those guys? We must have been waiting for fifteen minutes!"

The doctor chimed in, "I don't know, but I've never seen such inept golf!"

The priest said, "Here comes the green-keeper. Let's have a word with him." He said, "Hello George, what's wrong with that group ahead of us? They're rather slow, aren't they?"

The green-keeper replied, "Oh, yes. That's a group of blind firemen. They lost their sight saving our clubhouse from a fire last year, so we always let them play for free anytime."

The group fell silent for a moment. The priest said, "That's so sad. I think I will say a special prayer for them tonight."

The doctor said, "Good idea. I'm going to contact my ophthalmologist colleague and see if there's anything he can do for them."

The engineer said, "Why can't they play at night?"

2 plus two equals 5 for sufficiently large values of 2

Two male mathematicians are in a bar. The first one says to the second that the average person knows very little about basic mathematics. The second one disagrees, and claims that most people can cope with a reasonable amount of math.
 The first mathematician goes off to the washroom, and in his absence the second calls over the waitress. He tells her that in a few minutes, after his friend has returned, he will call her over and ask her a question. All she has to do is answer one third x cubed.
 She repeats "one thir -- dex cue"?
He repeats "one third x cubed".
Her: `one thir dex cuebd'? Yes, that's right, he says. So she agrees, and goes off mumbling to herself, "one thir dex cuebd...".
 The first guy returns and the second proposes a bet to prove his point, that most people do know something about basic math. He says he will ask the blonde waitress an integral, and the first laughingly agrees. The second man calls over the waitress and asks "what is the integral of x squared?".
The waitress says "one third x cubed" and while walking away, turns back and says over her shoulder "plus a constant!"

from http://www.math.utah.edu/~cherk/mathjokes.html