Movies with unforeseen changes in tone, theme, or style?

[sahrilcandra]

You ever watch a film where somewhere, whether early on or in the middle, the movie changes in a big way? Like what seems to be a comedy becomes drama, or what seems like a story about adolescents growing up and entering adulthood suddenly becomes a story about discovering a major crime?
I enjoy movies that do that because I have a tendency to anticipate how a movie will go and when I feel I know it, I stop caring. But movies that surprise me gets me engaged and involved again.