The folks at TED talks recently launched TED-Ed to serve the mission "of capturing and amplifying the voice of the world's greatest teachers." more 
In addition to developing a library of instructional videos, they've just added a free set of tools that allow teachers to create customized lessons from existing videos on TED, YouTube or YouTube for Schools. 

Open a free account at TED-Ed. Once you have selected a video, it will publish to it's own unique URL. You can share the lesson with students and others via e-mail, Facebook, or Twitter. It will exist on its own unique page on TED-Ed, and you can decide who gets to see that page.

Screen shot of TED-Ed interface ...  yes, that's me in the '80's

In addition to framing a video for your students, you can create multiple choice and open-ended questions, and add additional readings or activities to each lesson you create. After you have shared your lesson, you can log in at any time to see who viewed your lesson, the number of questions they attempted, the answers they provided, and, in the case of multiple choice questions, the number of questions they got right (with their permission, of course).

Want to know more about flipping your classroom - see more posts on my flip tag.