At the end of the "extended" run of The Melancholy of Haruhi Suzumiya on TV, which added 14 episodes of new episodes to the original first season, a teaser trailer for a movie entitled "The Disappearance of Haruhi Suzumiya" appeared, reportedly scheduled for 2010.
The movie shares a name with the fourth volume of Nagaru Tanigawa's light novel series about a young girl who unknowingly warps reality based on her perceptions, and the four special teens who join her "club" in order to keep a careful eye on her. The fourth novel in the series begins when the narrator Kyon finds himself in what appears to be an alternate version of the Haruhi universe, where the world is distressingly normal.
The first season of Haruhi aired in 2006, while the latest season stirred some controversy by weaving new episodes into a supposed re-broadcast of the first season. The 14 new episodes included the infamous "Endless Eight" arc, which consisted of 8 nearly-identical episodes in sequence and serves as a prelude to the Disappearance movie.
Source: Anime News Network