What movie is unexpectedly brilliant?
The Fast and the Furious: Tokyo Drift.
It's really quite good, but good luck finding anybody who hasn't seen it who would take it the remotest bit seriously.
Lots of people have very strong prejudices against the culture represented by the Fast and Furious films in the first place, and series fans themselves view it unfavorably owing to its sharp departure from the other films' main characters. Most people attempting a viewing don't have much patience for the film's knuckle-headed main character.
However, it is very much worth sitting through as a standalone film. It's beautifully shot, and presents an excellent case study in character growth through Sean Boswell's journey towards finding a sense of personal responsibility - if in an unconventional way - in a foreign culture that he learns to respect. In many ways, to me, this movie encapsulates all the best things that the Fast and Furious series has to offer in the most concentrated, focused, and real-feeling package.