I pick on blondes in the joke below, mainly because my wife is blonde. But my golden rule of joke telling is to personalize the joke for your audience — so feel free to replace blondes with graduate students, liberal arts majors, math professors, or whatever other group you happen to be speaking to.
Two blondes walk into a bar and order two shots. They clink the glasses, yell, “Four weeks!” give each other a high five, and throw back the shots.
They order two more. The bartender obliges. Again, they yell, “Four weeks!” and throw back the shots.
They order another two. The bartender says he’ll be happy to pour them another round, but first he’d like to know what they’re celebrating.
“We finished a jigsaw puzzle in four weeks!” explains one of them.
The bartender is confused. “And…?” he asks.
The other exclaims, “The box says 3–6 years!”