My posting yesterday on global population made me think of one of the best social commentaries to hit the theaters since Muffin Man. 
Idiocracy is a scathing remark on one of the worst trends of modern times: educated and intelligent people are having less kids and uneducated and lower intelligent people are having more. The movie projects this out 500 years to a society that is .... well, akin to 500 generations of Homer Simpson inbreeding with his second cousin.
Nothing is sacred in this movie - they take on pop culture, pollution, corporate marketing, government incompetancy, and the religious right (which is primarily responsible for humanities lowered IQ in the first place.) I love it!