Many math teachers lament the dearth of good math videos. How many Friday afternoons have you thought how great it would be to be a history teacher and just pop in one of thousands of video they have? From some one who has shown "Donald Duck in Mathemagicland" maybe a millions times, the value of a good math video cannot be overstated. I was somewhat surprised to see how many good math related things there are on the PBS website. I literally stumbled on to (via http://www.stumbleupon.com/) a video entitled "The Great Math Mystery". It can be found at http://www.pbs.org/wgbh/nova/physics/great-math-mystery.html. I think it's good. It perhaps tries to do a little too much, but it is a quality video. It shows many good applications in mathematics. It doesn't get into the nitty-gritty of the math, making it showable to pretty much any level of student. And at 53 minutes, you could probably milk it for two days worth.
Along with other videos, there are also a number of well-written articles. For example one called "Describing Nature with Math" is at http://www.pbs.org/wgbh/nova/physics/describing-nature-math.html. There are quite a few more you can find in their "physics & math" section.
