I watched a horror-and-coming-of-age film (think an arty version of "Carrie") called "Excision" last weekend, and was delighted to find that it had in it Malcolm McDowell in it, playing a high school math teacher. Not only that, but he teaches his students linear algebra (pretty advanced high school kids, eh?). There is a scene in which he questions his students about Cramer's Rule, and the whiteboard contains a fair amount of plausible-looking matrix theory, though I'd have to look at it again to know if it's legit (I was watching the movie in a theater at the time, so couldn't pause and ponder). Unfortunately, there was a glaring typo on the board: it says "Le A be an n x n matrix ..." Yes, "Le" instead of "Let." So sad that they messed up the English part of the math!

Be warned: it's not for people who don't like horror or gore.