Copy/pasted from another post... SPOILERS, obviously:

Okay so, in the books, The Volturi comes to town to fuck shit up because they found out about the Demon baby and think its dangerous, so the Cullens get an army together to fight. And then the Volturi show up and basically sit down for crumpets and tea and a chat and a whole lot of nothing happens because Alice shows up at the last minute and shows Aro (the lead Volturi guy) the future to assure him that Demon Baby is a cool bitch. And Aro's like "oh ok cool" and they leave and everyone lives happily ever after and its the stupidest fucking thing ever.

But in the movie, the same thing happens, and Alice shows up at the last second and shows Aro the future, but then she stops and is like "Wait a fucking second, you're planning to kill us anyway? Dick." And she fucking roundhouse kicks the motherfucker in the face and starts a war. So Carlisle is like OH HELL NO and runs toward the Volturi and Aro literally just rips his head off and sets him on fire and he's dead. And then Bella and Edward go into whoopass mode and Bella actually becomes badass for once and they start killing all the Volturi. And Jasper gets beheaded and set on fire and Seth the baby wolf gets really graphically crushed and dies and his sister Leah falls off a cliff to her death and Alice beats the shit out of Dakota Fanning and Edward falls off the cliff and Bella's like WHAT THE FUCK and saves him and then they kill Aro. Keep in mind this battle scene literally lasts about thirty minutes.

And then it flashes back to Alice showing Aro the future and he is basically shitting his fucking pants because he just saw the future of him dying and he's like "OH SHIT LETS GET THE FUCK OUT OF HERE" and everyone leaves.

I loved it because it honestly felt like it was making fun of the fact that nothing happens in the book and its glorious and all the little white fangirls in the audience were sobbing in terror. It was beautiful.