http://channel9.msdn.com/Events/aspConf/aspConf
it says "The video is not loading properly, this is a temporary problem...."
it's not so temporary, apparently. eventually it says "The video is not available at this time. Retry."
I'm not sure what happened. I was watching the live stream (although delayed by several hours) just fine and then it stopped.
This has happened at several events previously (PDC and build, I think) where there has been a seekable live stream that was taken down before the session videos were available. Please don't do this 
