I liked when I found out about the Erdős–Bacon number
http://en.wikipedia.org/wiki/Erd%C5%91s%E2%80%93Bacon_number#Actors
OMG, I just checked the Wikipedia article and found out that Mayim Bialik has a Erdős–Bacon number and she actually has PhD in neuroscience! TBBT has already have had Danica McKellar as a guest star. Now they only need Natalie Portman.
WTF. I just googled “mayim bialik neuroscience Erdős–Bacon number” and I turned up a hit on what I just posted 5 minutes ago.
A philosopher, a psychiatrist, and a priest stare down at the utter carnage of a plane wreck. The philosopher muses “this can’t be ‘the best of all possible worlds’”. The psychiatrist concludes “the pilot must have been insane”. The priest affirms that “this proves God is always in control”.
All three were looking at the bumper sticker at the end of the plane:
God is my co-pilot.
Nitpick: You mean Tantalus, unless this is a chemistry joke and I’m missing something.
I’m not sure if I made this up, because it occurred to me here a few months ago to make a point, not a joke, per se. So I’m not sure if I heard it before, or made it up on the spot:
How many mathematicians does it take to screw in a lightbulb?
0.999999999999999999…
As the Wikipedia article points out, in order to have an Erdős–Bacon number, a person has to have both appeared in a movie and have co-authored a scientific paper.
So I assume that somebody who has either never appeared in a movie or has never co-authored a scientific paper who have Erdős–Bacon number of Aleph-null. But somebody who has never appeared in a movie and never co-authored a scientific paper who have Erdős–Bacon number of Aleph-one.
Yeh, okay, it’s an old one.
OK - The OP asked for jokes requiring knowledge in multiple areas so I removed my stats joke. However, since many people are sticking to one subject area I’ll put it back.
Q: How many statisticians does it take to change a light bulb?
A: That needs to be solved using a non-parametric procedure because statisticians are not normal.
Haven’t read the rest of the thread, but this one made me giggle and immediately think of who I can pass it on to. Win!
When my kids were toddlers, I got them t-shirts that said ENTROPY ELF. I got one chuckle out of that, once. It was from one of the chem majors running the demo table for the Chem Department at UCD Picnic Day. (They were using liquid nitrogen to freeze things.)
I stole this one as well, but I don’t remember from where. It is one of my fave jokes. But alas, nobody ever gets it.
Maybe I should stop saying “alas”. ..
Two bears jump into lakes at the same time, one in California and one in Alaska. Which one dissolves first?
The one in Alaska, since it’s polar.
A cave-man family is sending their cave-boy to school so he can evolve and get smarter. One day, they ask him how school went. He said “It was OK. I missed the bus, but I managed to get a ride from my friend who lives over in Hamilton.”. His parents were aghast at this-- “Don’t you know that if you commute with the Hamiltonian you’ll never evolve?”
An infinite number of mathematicians walk into a bar. The first one orders a beer. The second orders half a beer. The third, a quarter of a beer. The bartender says “You’re all idiots”, and pours two beers.
(e^(pi * i))^2
You have to get up pretty Euler to get that one.
There is a chemical element named tantalum, which was named for Tantalus.
Or have a link to Wolfram|Alpha on your start page.
http://www.wolframalpha.com/input/?i=%28e^%28pi+*+i%29%29^2&t=igg01
It took me a while to get the joke in the “Tortoises” movement of the Carnival of the Animals - the tune is Offenbach’s famous can-can played very slowly. 
Chemist joke:
If you are not part of the solution, you are part of the precipitate.
Or |e[sup]ip[/sup]|