Found at Majikthise, Lawyers Guns and Money, and Lance Mannion, and apparently originating here: choose ten movies that you would show to someone to explain America to them. Here's my list, off the top of my head, making some effort not to duplicate the others.
The Player (1992)
Cool Hand Luke (1967)
Training Day (2001)
Metropolitan (1990)
Easy Rider (1969)
A Streetcar Named Desire (1951)
Hoop Dreams (1994)
The Sting (1973)
Glory (1989)
Dr. Strangelove (1964)
I thought at first it would be hard to think of ten good ones, but I ended up having to leave out Fargo, One Flew Over the Cuckoo's Nest, Thelma and Louise, The Conversation, The Untouchables, Blue Velvet, and a bunch more. I'm not providing any explanations for my choices -- figuring it out should be half the fun.