I say that the glass is completely full - half of it contains air and the other half contains whatever liquid in question. 
Q. What do you get when you cross a mosquito with a rock climber?
A. You can’t cross a vector with a scalar.
You must mean “from 1 to the cube root of 3”.
And if some of you don’t like “zed”, try “t squared dt”.
Greatest Intellectual Prank ever:
“Did you know that gullible isn’t in the dictionary?”
I’ve lost four very close relatives at Memorial Sloan Kettering Cancer Center. My mom has been going there for years and has survived breast and ovarian cancer thanks to the doctors there. Last year, the doctors at Sloan found cancer in her nose and had to remove most of it. Even after the reconstructive surgery, she has a permanent scar running from the top of her forehead to the base of her nose.
I wonder if she would find this funny? I certainly don’t.
A slightly different version:
An internist, a surgeon, a psychiatrist, and a pathologist go duck hunting.
They are sitting in the blind, waiting. The internist looks up. “Look,” he says, “I think there’s a duck up there… yes, it’s a red-tailed mallard. Very unusual to see this species in this latitude this time of year, though technically that species is properly subdivided into blah blah blah blah…” By the time he’s done talking, the duck has flown away.
The psychiatrist looks up. “I think there’s a duck up there!” he exclaims. He closes his eyes, points his shotgun up and starts randomly blasting volleys into the air. Needless to say, he doesn’t hit anything.
The surgeon looks up, grunts, raises his gun, and fires. A bird comes tumbling down. “Hey,” he says, turning to the pathologist, “go see if that was a duck.”
How many economists does it take to change a light bulb?
None. The conditions for lighting are already there.
Three auto mechanics and a software engineer take a ride in a car that unexpectedly stops in traffic and won’t start.
First mechanic: No spark. Nothing we can do about it without any parts or tools.
Second mechanic. No, there’s no fuel. Maybe someone with a gas can will stop.
Third mechanic. No, there’s no air. Check the hoses.
Software engineer: How 'bout we all just all get out of the car and get back in?
Q: Why is a bird?
A: Because a vest has no sleeves.
When teaching classes at Fire School, I like to ask new trainees:
“What is in water that extinguishes fires?”
After hearing the expected responses of cooling capacity, breakup of the fire tetrahedron, oxygen removal and so forth, I give them the answer.
“Fireboats”
A new hospital opens in Inverness, and Tony Blair tours it not long after the first patients are admitted. As he strolls down a ward, in the company of the head physician, he decides to chat with the patients.
“So,” the Prime Minister asks, “How are you feeling?”
The patient fixes Mr Blair with a penetrating stare and decalres “Scots wha’ hae wi’ Wallace bled, Scots wham Bruce hath aften led, Lie now in thy gory bed, Or on to victorie!”
“Yes,” the Prime Minister says, somewhat startled, “I see. Carry on, chap!”
Moving on to the next bed, Mr Blair says “I say, how are you feeling?”
The patient looks up and replies “My love is like a red, red rose that’s newly sprung in June. My love is like a melody that’s sweetly played in tune…”
The Prime Minister turns to the Head Physician and says “What is this - the mental ward?”
“No sir,” the Doctor replies…“Serious Burns Unit!”
Same joke, different casts/punchlines: (Funnier, IMHO)
Accountant/“Red ink - debit, black ink - credit”
Sea Captain/Port - left, Starboard - right
The bartender says, “What is this, a joke?”
Sixteen years. Helluva bump, not to mention a first post and, tbh, not that intellectual a joke. Welcome to the SDMB but do try harder. Here is some more erudite fare:
Q. What’s an anagram of Banach-Tarski?
A: Banach-Tarski Banach-Tarski.
Are Calvinist priests pre-ordained?
A music theorist walks into a bar and says “I’ll have a gin and dominant, please.”
The bartender asks, “What’s a gin and dominant?”
“It’s like a gin and tonic but you add a whole fifth.”
One that I started a thread with, several years back:
Q: How do you ruin King Kong for a Cognitive Psychologist?
A: Have him count the number of times the basketball is passed.
If you’re not laughing discreetly in intellectual appreciation:
[spoiler]
http://www.theinvisiblegorilla.com/gorilla_experiment.html
My earlier thread – How do you ruin King Kong for a cognitive psychologist? - Mundane Pointless Stuff I Must Share (MPSIMS) - Straight Dope Message Board
Two guys walk into a bar. The bartender asks them “What will it be?” The first guy says “I’ll have a tall glass of H[sub]2[/sub]O.” The second guy says “That sounds good, I’ll have H[sub]2[/sub]O too.” The second guy died.
Q: Do you know any good jokes about sodium?
A: Na.
I would tell more chemistry jokes, but all the good ones argon.
One from the Hitch
Why was the Amish girl disowned by her family?
Too Mennonite.
Or (attribution unknown)
Mrs. Schroedinger: “Erwin, what the hell have you done to the cat? it looks half dead”
Q: How many poli-sci profs does it take to screw in a light bulb?
A: Three. One to argue it should be turned to the right, one to argue it should be turned to the left, and one to get the grad student to do the actual work.
How many fruit flies does it take to screw in a light bulb?
2
Three logicians walk into a bar. The bartender asks the first one if they all want beer. He answers: “I don’t know”. The bartender asks the second if they all want beer. He answers: “I don’t know”. The bartender asks the third if they all want beer. He answers: “Yes”.
Einstein and Heisenberg are traveling to a conference in Heidelberg. Einstein is driving and Heisenberg is in the passenger seat with a map, navigating.
Einstein remarks “we are traveling west at 83.1 km/hr”
Heisenberg: “Dammit, now we’re lost!”
Yeah, 2. But don’t ask me how they get in there.