The world of physics jokes is fairly small. You can get a good impression of them by wandering around a physics department and looking for the people who put them up on their doors. For the most part, they're mostly "in" jokes. For example, one gives a transtlation table between phrases you commonly find in physics papers (for example, "it can be shown") and what is "really meant" ("my grad student worked this out, I have no idea if it's correct"). You basically have to be a professional physicist to find this sort of thing funny.
Even worse are the jokes in various sub-fields of phyiscs. For example, in my field, high-energy physics, the most recent joke was this preprint posted on April first. This is really funny, if you've had two graduate level courses in quantum field theory and are familier with the latest work in string theory. Otherwise, you'd be hard pressed to distinguish it from any other paper in the field.
There are a few physics jokes that can be apprciated by everybody though. The best has been around for a few years, the strange case of MC Hawking. The premise of this site is that noted theoretical physicist Steven Hawking has had a modestly sucessful second career as a gangsta rapper. Needless to say, not everybody will actually find this funny, given
Prof. Hawking's disability, he is confined to a wheelchair, cannot move anything apart from his head and hand, and speaks only with the aid of a computer. However, Dr. Hawking (the real one, not the fictional gangsta rapper) takes the joke in good humour.
What's more, the guy who is actually responsible for the joke (Ken Leavitt-Lawrence, not a physicist) has some reasonable skills putting together rhymes and beats, and the speech program he uses sounds exactly like the real Steven Hawking. The MC Hawking website used to have a few mp3 files of various MC Hawking raps which you could download. Demand was so high that a CD has been released, "A Brief History of Rhyme: MC Hawking's Greatest Hits". As a fan of both theorectial physics and gangsta rap, I had to have it.
The CD arrived yesterday, and I can definatly recommend it. If you've ever wanted to hear Steven Hawking gangsta rapping (and he doesn't hold back on the foul languauge) it doesn't disappoint. Highlights include the classic "All my shootings be drive-bys", in which the Hawkman takes care of some punks from rival MIT, "Bitchslap" which
details how MC Hawking deals with a disrespectful TA, and the duo "The Big Bizang" and "Entropy" which explain the Big Bang theory and the second law of thermodynamics via rap. The only track missing is the ode to first person shooter video games, Quakmaster. You can get that on the MC Hawking website.
My personal fave is "F**k the Creationists", which is particularly appropriate given the sillyness going on these days in Kansas (and elsewhere).