The 2010 Movie of the anime: "The Melancholy of Suzumiya Haruhi".
A new world is born where there's no more S.O.S. Brigade, and no one remembers it. Kyon tries desperatly to understand what happened to all is friends and why everyone doesn't remember anything. In the process, Kyon tries to make everything go back to what it used to be, unfortunatly, heยดs not the only one aware of this "new world".
This is one of the best movies I have ever seen! The story is great and only gets better as it progresses (but it gets a little big confusing near the end).
I recommend this to all Haruhi Suzumiya fans and although it is watchable if you haven't seen the series's I think you should watch them before you watch this because it has a lot of references to the series and scenes from them.
Also, and this is quite IMPORTANT as you may miss this if you skip ending themes/credits but there is something right at the end so make sure to watch it to the end.