Check out the Stargate Studios 2009 Virtual Backlot Reel for a fun look at the use of green screens. I’m sure you’ll recognize several of the shows included in the reel. Of course, the Ugly Betty scenes are from before filming moved to New York. Crazy how much of what they did was green screen back in season one, eh? I remember watching the featurette on the season one DVD and being amazed how much the actors have to pretend is there.
If you want to see more, Stargate has a few more reels up on their website. Their driving demo is probably my favorite, if only because of how it’s the one green screen effect that I notice the most in my favorite shows.