Musings on the Three-Act Structure

So in my 20th Century Boys I made reference to the Hollywood three-act structure, and it got me thinking. Because, when it comes to writing, I’d be loathe to assert that the Hollywood formula is the pinnacle of writing, I’ve been thinking about what films successfully go with something different.

No Country for Old Men  - The Coen Brothers are quite good at this as a whole. It's been too long since I saw Fargo or The Big Lebowski to comment, but NCfOM is a terrific example. For much of it's time on-screen, it seems to be more or less typcial thriller with a western taste to it. Everyone talks with that deep south parlance, but otherwise it is a thriller about a man being chased by a cold and ruthless killer. At his home a detective tries to work out what happened, why this man is chasing them and who else is involved. But what is actually happens in this story is that the old sheriff is main character here, and it is his story we are following. Thus when we get to the third arc, suddenly it's all change and all of the pay-offs are wrong and the film's final scene is, well, unexpected. There's a couple of fake arcs in here, but this is a very unconventionally structured story.

Pulp Fiction - Pretty much all of Tarantino's films have convention breaking structures too, and Pulp Fiction is the easiest and most obivous one. We see our heroes' journeys in the wrong order, and getting resolutions before and after journeys. If you've seen the movie, this one is pretty self-explanatory really.

And suddenly I'm scrambling for examples. Trainspotting probably does this, but I'd need to rewatch it to refresh my memory. I remember lots of people claiming that Scott Pilgrim Versus the World doesn't follow the three-act structure, despite the fact that I see three very clean cut and obvious acts. Hell, Ramona even changes her hair colour to tell you that a new act has begun.

There is a common trend in writing to embellish the three act structure with a very short fourth act. Only highlight the following text if you've seen Alien, which has a very good example of this: When Ripley has gotten off the mainship, escaped onto that shuttle - there is a cool down, a drop in tension. The movie feels finished. Then it turns out that she can't just escape the alien, she has to defeat it too, because the alien has followed her off the self-destructing main ship. Basically, this establishes that the supposed climax of the movie was misdirection, and now we get to see the real climax. It's fairly common and abide to the the three-act rule pretty hard and fast, so it doesn't really count as breaking out of that structure. Christopher Nolan seems fond of doing this too, what with Inception and The Dark Knight both doing this.

So am I overlooking some obvious ones? Are there any better film examples of unusual structuring? Is this a big gap in my knowledge, or is it rare to see good movies not using the three act structure?