Everyone here is probably thinking of the DeVinci code when I say this, but I'm thinking in a broader sense.
My favorite movie misconception has to be from that cinematic masterpiece, The day after tomorrow, where the protagonists are running down the hallway of the library trying to escape the cold blast of air that flash-freezes everything it touches. The brilliant explanation for why this happens is that the storm is "pulling down" air from the stratosphere "too fast" so it "doesn't have a chance to warm up." Practically every word in that sentence is wrong in some way:
storms cannot "pull down" air from the stratosphere, no matter how strong they are, because the stratosphere is a stable layer of air that prohibits processes lower down from effecting it. Even the most powerful supercell thunderstorms will only have a little area where the strongest updraft punches through to a stable layer.
assuming the storm COULD pull down stratospheric air, how cold is that stuff anyway? A quick look at a sounding taken from a weather balloon in Canada tells me that the temperature near the top of the sounding, right at the lower levels of the stratosphere, is around -60 C, which is about -76 F. Is that cold? Sure it is, but not unheard of in really high latitudes during the winter, at least with the wind chill.
What really happens if that air were to be "pulled down" to the surface. Well, to answer this question we need to think about thermodynamics. What happens when you press down the piston in a tire pump? The air pressure in the pump rises. What happens to the air because the pressure rises? it gets hotter. What happens to the air pressure when you go higher in the atmosphere? It lowers. Reverse that statement, and you can say that pressure increases as you get lower in the atmosphere. If a glob of air were to be "pulled down" to the surface from the stratosphere like in the movie, it would actually warm up, quite a lot actually. Another quick look at a sounding tells me that the potential temperature (the temperature that the air being pulled down would have when it reaches the surface) is about 170 F! talk about a heat wave!