I've been showing YouTubes in class on Wednesdays for several years now. Usually I'll show 5 or 10 minute clips of an educational YouTube something to do with what we are learning in class. I have several students in Computing and Math classes, so I try to show something different in each.
Lately, I've been showing NOVAs. There's a good one from 1985 called the Mathematical Mystery Tour about the great unsolved problems of Mathematics with interviews of some of the top Mathematicians of the time about how they do math.
I've also been showing one in my Computing classes about Clifford Stoll and the Cookoo's egg virus. I think this one is from around 1988 and its all about the dawn of the internet and a ring of hackers Clifford tracked down while working in the IT dept at LBL.
The last year has seen a number of new NOVAs that are very good. One is about the life of Beniot Mandelbrot in particular and fractals in general.
Another NOVA that was on last week was about the IBM supercomputer called Watson and a match it had against some Jeopardy champions. My Computing Independent Study class is upset with Watson. They've been working hard all year to get all 50 cores in my classroom to work as a single Linux Cluster. We finally harnessed all 50 AMD 64bit Athlons and got Shadowfax running at 24 GFLPOS. Well, Watson runs at 72 TFLOPS and has 3000 processors. So, Watson is 3000 times faster than Shadowfax and one of Watson's cores is equivalent to all our 50 cores put together. In other words, my entire PC Lab/Classroom/Cluster is just one chip out of 3000 on Watson....