The Revit user community cretes many video tutorials. Below are links to some user created video playlists.
Steve Stafford is a long time Revit user and consultant. Steve also regularly writes Revit tips and tricks at his blog Revit OpEd. Many of his articles include videos. The following playlist links to all of Steve Stafford's videos.
Aaron Maller is a Revit user who wroks for Beck Group. See the videos he has made avaliable to the Revit community.
The author of the Architect's Digital Design Guide, David, Beach has posted 26 of his Revit tutorials to YouTube.
If you have your own playlist, or know of other playlists please add them to the list here. If it is your own playlist consider adding the videos directly to the wikihelp. Then embed the videos into the relevant help topic.