The premise: 20 years ago, an alien mothership arrived at Earth and stops over Johannesburg, South Africa. The aliens wind up being stranded on Earth and treated as third-class citizens, forced to live in military-controlled slums designated as District 9, or D9. The movie is more a social commentary on the apartheid era (Blomkamp is a native of Johanneburg) and xenophobia. A clueless MNU bureaucrat, Wikkus van der Merwe, is infected with an alien fuel-type fluid while serving eviction notices to the aliens of D9, and becomes the target of not only his own employers, who wants his ability to operate alien weaponry, but Nigerian gangsters for the same reason. He hides in the one place he knows no one is looking for him -- with the aliens. Wikkus becomes more humane toward the aliens as he loses his own humanity, and in the end... well, there are so many ways this movie can go, I don't want to spoil it all for you. 
The premise: A man claims to be an alien and gets shipped off to a psychiatric ward where he teaches the other patients and the doctors themselves a few things about being human. This is one of those touchy-feely, mostly-sweet movies that makes me happy every time I see it, and not just because of the way Kevin Spacey eats a banana (it's one of the funniest fruit moments in the history of cinema, I think). I can't really say too much about it for fear of giving it all away. Not to get too woo-woo and not to spoil it for you, but Prot is what I'd term a walk-in Starman/wanderer. (A walk-in is thought to be a person whose original soul has departed his or her body and been replaced with a new soul.) 
The premise: A group of aging, forgotten actors of an old science fiction TV show relive their glory days at sci-fi conventions signing autographs and hosting panels about their space traveling show -- until real aliens show up and and beg them for help, thinking they really are the space-faring action heroes depicted in the TV show. This is a classic Star Trek parody that made me want Sigourney Weaver to do comedy more often because she's fantastic at it. There are points where I find I'm laughing at myself because I'm a big Star Trek nerd and I know exactly what aspects of the show they're ridiculing. When I need to laugh out loud, this is the one I put in the DVD player.
The premise: the Men in Black really do exist and they protect the planet from all sorts of alien threats, as well as policing and organizing the aliens who live peacefully among us. Hilarity ensues. 
The premise: Aliens come to Earth... and try to destroy it. Apparently the alien ship that crashed in Roswell was a scouting party to see if our planet had enough resources for their race to strip mine the planet and move on, destroying humanity in its wake. This is just a good shoot-'em-up space flick. Bill Pullman does a better job playing the President than most politicians do. And Brent Spiner's role was entirely too short in this movie; he's a far better actor than to only be remembered as Data on Star Trek: The Next Generation.
