Two mathematicians were sitting on a bench facing a building. Two people walked out of the building. A few minutes later, one person walked into the building.
One mathematician turned to the other and said, “If one more person walks into the building it will be empty again.”
Probably something I’ve seen on Futurama, which has a number of geeky jokes I’ve only noticed because of Wikipedia. Or better yet, some joke I didn’t even notice because it flew way over my head. That’s what happens when guys with doctorates in advanced math write a comedy show. 
Hypothetically, if I worked for a large insurance company, and someone ran a piece of SQL last Thursday night that went something like:
UPDATE POLICY_TAB
SET POL_EXPIRY_DATE = ‘01.08.2008’;
against the live tables, and I mentioned it here, I’d been in deep doo-doo, so I’d better not. (But being at home at the moment, even a keystroke logger is nothing for me to fear.)
Place I worked for 12 years ago, a new hire pretty much irretrievably destroyed our database by doing a (clipper) “rebuild index” command and then shutting down the computer when it took longer than she expected (probably everything was normal, but I guess she panicked). We had to restore from the latest backup, which was almost a month old.
She was let go.
You beat me to it. So, I will contribute:
A neutron walks into a bar. He asks the bartender, “How much for a beer?” The barman replies, “For you, no charge.”
Along with whoever was responsible for the backup policy, I hope?
I don’t get the “Sudo make me a sandwich” strip.
Geekiest joke I know is from college physics. The professor drew a caterpillar on the chalkboard. It was laying on its back with its feet in the air, and had two little Xs for eyes. She said you would call this an erg, because it’s a dine centimeter.
“Schrodinger, what have you done to the cat? He looks half dead!”
sudo is the UNIX command to give yourself “superuser” (godlike) powers…
Check out post #20.
The “>” is what you get for having a “$G” in your PROMPT variable. Windows uses the ever-useful $P$G as its prompt - $P gives the drive and directory.
You could concoct some fairly elaborate prompts - at the low end, “prompt $D $T $P$G” will give you the day, date, time and path. $D T _$P$G puts that on two lines. You could even do ANSI/ASCII graphics. One classic was the Texas state flag:
PROMPT _$$e[22;3H$e[1m$e[44m $e [47m$e[23;3H$e[44m * $e[47;41m$e[24;3H$e[44m $e[41m $e[40m $p$g$e[0m$e[2C
Unfortunately, Windows just chokes on this - it only works on real DOS that wasn’t being interpreted through a Windows kernel.
I like to tell it with a chlorine atom and a sodium atom.
Someone at work told it with two hydrogen atoms, but I told him that a talking proton would just be silly.
I don’t get it.
hex is base 16 - the digits are 0-9,A,B,C,D,E,F, where A = 10, B =11, and so on. DEAD is a legitimate hexidecimal number, which is equal to 57005. DEAD people and you is then 57006
Walton Firm:
Company owner’s son.
Oh. My problem was that I was reading it upside down as GOOLS. (Which may or may not be accurate.)
What’s sour, yellow, and equivalent to the axiom of choice? Zorn’s lemon.
What’s purple and commutes? An abelian grape.
Mathematicians: Making computer scientists feel better about their jokes since 1842. 
Conserve energy: Commute with a Hamiltonian.
While checking out girls back in my geeky high school days, I would comment on a passing beauty with, “She makes me want to maximize the function of my natural log.”
Three Statisticians went duck hunting. The first took his shot. A meter high. The sceond got up and took a shot. A meter low. The third jumps up and yells “We got him!”.