From Cosmic Variance
The spheroidal distribution of stars in the centers of rotating disk galaxies is called the “bulge”. Now, introduce a bunch of bored and horny 19 year olds into the mix, and you have a dangerous cocktail. One of my colleagues lost complete control of a 250 person lecture class when she had two male students hold up pictures of different galaxies, while she expounded on how “This guy over here has a small bulge, but the bulge of this guy is quite prominent.” The titters started as she forged ahead unknowing, until the entire class collapsed in hysterics. At that point, you just have to put down your laser pointer, send the class home, and head for the bar. Learning is over.This reminded me of how my classes in quantum mechanics taught me about the mathematics of bras.