If you’ve read the seventh Potter tome … or if you’re not going to read it, but still want to know how everything turns out in the ever-loving end … then do I have the end-all-be-all of almighty spoiler-ation. Allow me to introduce: Potterdammerung!
A non-spoiler-ly excerpt:
Harry: I’ve been thinking and–
Ron: You think it’s too dangerous.
Hermione: And we shouldn’t come along.
Harry: How did you know that?
Hermione: Harry, you’re a good guy, but as characters go you’re kinda predictable. And anyways, we are going.
Now, carry that kind of lovely snark through the rest of the plot (stopping along the way to make just about every Death Eater speak like a LOLCat), and that’s the degree of brilliance that awaits you.
But seriously … if you don’t want to be spoiled for the turns of fate in Deathly Hallows, do not follow the link, because the poster (Sean O’Hara, it says) holds nothing back.