I love interactive sites pertaining to TV shows or movies.
LOST:
http://www.flyoceanicair.com/
http://www.find815.com
ReadWriteWeb talks about it.
When will campaigns like this become part of the experience, and not just a promotion for the show?
The first one I can remember is for Starship Troopers. They had a great game that replicated the style of the movie and built up a great following people who were excited for the movie months in advance. Too bad the movie sucked.