Vacancy (2007)

When David and Amy Fox's car breaks down in the middle of nowhere, they are forced to spend the night at the only motel around, with only the TV to entertain them, until they discover that the low-budget slasher movies they're watching were all filmed in the very room they're sitting in. With hidden cameras now aimed at them - trapping them in rooms, crawlspaces, underground tunnels - and filming their every move, David and Amy must struggle to get out alive before whomever is watching them can finish their latest masterpiece.

Official website: http://www.sonypictures.com/movies/vacancy/