The NCTM (National Council of Teachers of Mathematics) has several E-Seminars available on the web. A full list of available topics can be found here. If you aren’t an NCTM member, the seminars are $79 — but if you are an NCTM member, they are free!
Each seminar includes a facilitator guide, a PDF of slide show handouts, and a video of the presentation. The videos are approximately 60-minutes long.
The E-Seminar I just watched is called “Mathematics Teaching and Student Learning: What Does the Research Say?” Check out the description on their webpage.
It was my plan to head home by now but this seminar video captured my interest, so here I am, still in my office!