I thought Troll Hunter was great. I enjoyed Apollow 18 for all of it's faults (Gotta support my sci-fi brothers). It's hard to pin point exactly why I like these types of films. Maybe part of it is if it's done well enough you are dragged along right with the people involved and you always have this sense that it could be real. Guess I should get to work on my bigfoot found footage idea... -Jim

I know it's not a movie, but Orson Welles' original War of the Worlds radio broadcast is probably the granddaddy of this genre.