not at my place–it’s gone! 
50% of the people will say half full, 50% will say half empty and 50% won’t care.
serious mode
If you’re interested in how much is in there, it’s half full. If you’re interested in how much is not in there, it is half empty.
slightly serious mode
What glass? I don’t see a glass …
not-all-that serious mode
Do you mean a philosophical glass? Because then the glass is probably full … of sh*t!
way not serious mode
HEY! Ga ga ga ga. Woooooooooooooooooooooooooo … !
Ki ki ki kikikiki ki ki ki. (1)
Ki.
Kaboom
Ki ki ki.
(1)
Martian 1: Is that planet half green or half blue?
Martian 2: What planet?
Kaboom
sadistic laughter
From the point in life that I’m in, having 1/2 the glass remaining is just fine with me. If the last 1/2 is as great as the first I will need to get moving to finish it, even if I stay around for many years (knock, knock). 
The glass is twice as big as it needs to be.
Of what?
Just half.
An optimist would say it’s half full.
A pessimist wants to know how come the optimist got his glass first.
Since the purpose of a glass is to be filled with something then it is half full.
It is not possible to answer that question without further information, unless you posted a link that I missed. What glass are you talking about? Do you have a photograph of it?
That question is a bit like “How long is a piece of string?” The answer to that one is of course, “Six.”
The glass is…
shiny! is entranced by the glass
The glass is already broken.
There is no glass.
Now it’s empty. Another beer, por favor?
My Beer glass is made of plastic. So it’s a ‘plastic’.
My plastic is nearly empty.
The linguist prefers to diagram this sentence about the glass .
The scientist forms a hypothesis and wants six more glasses of precisely the same volume for his control group and to run some tests before offering his conclusion.
The Creatonist knows that God designed the glass and the water is only 5,000 years old.
The Baptist assumes it’s miracle there’s any fluid at all.
The Buddhist wonders if there isn’t some middle way.
The humorist pokes fun at the glasses’ “rim” “bottom” and “body.”
The sexist thinks the glass is just sitting around getting fat.
The feminist finds the glass offensively phallic.
(The sexist and the feminist will wake up in bed together tomorrow)
The post-modernist tries to make some statement about the glass that isn’t hopelessly hackeneyed or jejune.
The bi-polar feel one way sometimes aaaand sometimes another.
The paranoids don’t even want to touch the glass without gloves.
The realist is wondering: Wait, is the glass is clean?
The surrealist’s glass is melting.
The racist sees any glass that’s half-anything the result of rampant miscegenation and blames the Jews.
The politician won’t comment until his handlers give him the go ahead.
This “Klein Stein” could be simultaneously half full and half empty.
Come on, you’ve already got approximately 9x10[sup]24[/sup] water molecules in there, how many more did you want?
It’s a special decoy glass. The real glass is in a secret location.
To add to Askia’s list:
The salesman hopes a lot of people are stupid enough to pay more for a half-full glass than for a half-empty one.