I have never, NEVER, seen a movie like this.
Saying "District 9 is about aliens" is like saying "Harry Potter is about a boarding school". True as far as it goes, but there's so much more going on.
The basic summary (no spoilers, don't worry) is that aliens appeared over Johannesburg, South Africa, about twenty years ago. When they didn't emerge from the ship, troops went in and found them sick and dying. Not wanting to leave them to die, they brought the aliens down to Earth adn placed them in a 'temporary' camp called District 9. They've been there for twenty years, over the increasing objections of the local residents, and now it's time to move them to a more secure facility, District 10.
Needless to say, this move doesn't go exactly as planned, but the ways in which it doesn't surprised and amazed me. There were deeply gross moments, there were spots where the whole theatre laughed out loud, and I did get teary on two occasions. (But bear in mind I sometimes cry at TV commercials, so your mileage may vary on that one. :) This so isn't the typical "aliens appear over the United States" kind of movie, and I loved that. I left the theatre absolutely silent, my head spinning, and Mr. W and I have been talking about it for the last hour.
One down side: there's a bit of the "Cloverfield" style of filming. If you didn't see that movie, it's the "cam-corder" kind of thing, where it's constantly shaking. I didn't find this movie anywhere near as bad (I spent most of "Cloverfield" staring at my lap and wishing I didn't feel too sick to eat popcorn, and the people in our theatre for it actually cheered when the main cameraman died because we got a break from the shaking) but it did have its moments.
It's so worth it, though. It sometimes seems like everything out there is the same... one kind of book, one kind of movie, standard and predictable. This isn't that movie, and I hugely recommend it. At one point I found myself thinking, "Damn, I wish I'd written this story."
If you go, let me know what you think!