How to plot a story, South Park style

Imagine you're sitting in your writing class at NYU, minding your own business, when the door opens and Matt Stone and Trey Parker, the two creators of South Park, amble in. This video clip shows their lively lesson in creating a good plot. It's not about "and then, and then ...," it's about "but."
http://bit.ly/p9x8zD

p.s. I don't watch South Park, but my son likes to describe his favorite episodes, and it sounds pretty funny.