In April of 2005, a group of teachers from North East Ontario got together for a regional Leading Math Success working session and created introductory videos and powerpoints for six Math manipulatives. These were then used in local training events. When I let the participants know that they had been posted to a popular video sharing site, I got lots of replies and recollections about how worthwhile a professional development experience people thought it was - fodder for Judy's resume! The full collection of files has been posted for a while.
My contribution was a Geometer's Sketchpad sketch - a Fraction Circle tool and virtual manipulative.