This is a clip from "Idiocracy". I had never heard of the movie, but watched it "on demand" yesterday. I was rolling!!!! I couldn't find any of the clips I was looking for, but this one isn't bad.
[ame="http://youtube.com/watch?v=c2PldVocn7c"]YouTube - Idiocracy - Toilet Water vs. Brawndo[/ame]