I've thought for awhile that video taping a game could be done well. The real trick would be in the editing and in the players themselves. First, you'd need a moderately attractive group of players. Not that they'd all need to be supermodels or anything, but the last thing the world needs is a CPM on video roleplaying his lesbian drow assassin.
The editor is what could make it all work. Just a static camera taping a whole session would be boring and unintelligible. Different angles, and cutting out all the rules-talk would be required. Add in some good role players and 'reality tv' style confessions and you could really have something.