"Imagine hundreds of thousands of great short videos, and other media, explaining every topic taught to school kids. Imagine them rated and sorted into a giant Directory, making them simple to find. WatchKnow--as in, "You watch, you know"--is a non-profit online community devoted to this goal. "
A podcast on counting. Kids with younger siblings get a big kick out of it because it talks about how children develop a number sense. Also talks about the importance of mathematics in everyday life. I use it during my unit on logarithms.