As I type, District 9 is #98 on IMDB's list of the top 250 movies of all time. I don't know about that, but it's pretty good, if you can stand the (according to the MPAA) "bloody violence and pervasive language." Also not a little bit of thinly-disguised social commentary in the old Star Trek tradition. It's filmed in semi-documentary style, with interviews, bouncy camerawork, etc.
The story: decades ago, a huge alien vessel appeared in the skies over Johannesburg, South Africa, and just hung there. Eventually, the doors were pried open to reveal scads of starving ugly aliens. What to do?
Well, if you're a South African, what you do is move the aliens (dubbed "prawns" due to their appearance) into a segregated area called "District 9". Over the years, District 9 has become a hellhole slum, the prawns a constant irritant to the humans, preyed on by criminals, who exploit the alien addiction to cat food. (Apparently, the prawns are a lot less fussy than actual cats; they'll eat anything labelled "cat food.")
A plan is launched to move the prawns to an even worse location ("District 10"), and a petty bureaucrat, Wikus Van De Merwe, is sent into D-9 to commence the ostensible legal formalities. The mission doesn't go well, Wikus is infected with prawn juice, and starts transmogrifying. Suddenly, he's no longer viewed as human; he's simply an interesting specimen. Unsurprisingly, Wikus objects…
The IMDB is a source of hilarity. On their parental guide page, under the "Alcohol/Drugs/Smoking", the writer deadpans: "Some social drinking of liquor. If you'd call addiction to cat food drug abuse, this film contains plenty of it."
And one reviewer: "Worst RomCom ever!" (This is true: Mrs. Salad buried her head in her laptop for most of the movie, and was shooting me dirty looks during the rest.)
Without spoiling things much, the ending screams "sequel". Most speculation says it will be called District 10, although nothing's even in pre-production yet.