Teachertube looks and works much like YouTube, but you're much less likely to run across videos that Not Safe For the Classroom.
All of these videos are made by students and teachers. According to the Dallas News, there are 54,000 videos on the site already and 800,00 visitors every day.
I especially enjoyed watching Abbot and Costello doing math problems.
That's a coincidence. I showed my 6th graders that very video today. They had a fun time discussing what was wrong with the math and how it should be properly done. You should check out the math hip hop videos.
Know I am late to this party but loved the video and the site (though its feed seems terribly slow). Did you notice Shemp? That is the reason Curly was in the Three Stooges' shorts at first and not Shemp, who was an original Stooge. He was under contract to Universal.