Home Movie (2008) http://www.rottentomatoes.com/m/1218197-home_movie/
I loved this movie! It features no gore, no "BOO!" moments but ended up being one of the most frightening and suspenseful movies I've seen in a long time.
This is one of those films you'll be thinking about for days. You'll argue with your friends about the ending and whether it was really plausible or not and have fun watching it again picking up all the many clues leading up to the climactic ending. The last shot of the film is a culmination of all these clues showcased in one suitably epic scene. *shudders*
I personally felt that one critical moment before the finale was pretty implausible (one of those "surely they're not that stupid" moments), however, everything else that happened after is plausible (a few clues throughout the movie show quite clearly that the "troubled" offenders are more than meets the eye). I can forgive this though because it ratchets up the tension to an unbelievable level and makes way for a truly memorable ending.
I urge people to see this little known flick, it's a real gem. 8/10