"Paranormal Activity 2"

A scene from "Paranormal Activity 2" (Paramount Pictures)

Not only did the surprise horror hit "Paranormal Activity" frighten audiences when it came out last fall, it also shocked box office analysts by earning $194 million US worldwide, on an estimated budget of just $15,000. With the impending release of "Paranormal Activity 2" on October 22, we thought we'd look back at some of the smallest movies to make big bucks at the box office.