Bummer how backbone is free, railscasts was free (and still is mostly free), backbone tutorials are free... where am I going with this I don't know. It is sound from a business perspective, but it goes against the grain of the community.
peepcode has been charging for screencasts for years now
Screencast by some guy. Pay on $9 (usually $18) until November 8th. Maybe it's great, I'm not biting.