Catfish
Catfish is an documentary that often feels much longer than it needs to be, yet there's no denying that filmmakers Henry Joost and Ariel Schulman have infused the movie with a number of striking sequences and an (almost) consistently intriguing structure. The film essentially follows New York-based photographer Yaniv Schulman as he befriends a talented little girl over the internet, with his relationship with the kid eventually leading to a cyber-romance with her older sister.
(yes they developed this into a tv show)