I can see it now:
The End of the Seventh Book:
Harry had just killed Voldemort. His hands were covered in blood, whose blood he didn't know, as he was kneeling down beside Voldemort's lifeless body, in shock that it was all finally over.
He was in a dark, damp cave, as big as a gymnasium. He could barely see the walls of the cave, nor could he see the ceiling. Nothing lay around him but a pool of blood, Voldemort, and his wand, which Harry had dropped in final realization that his long time nemesis was gone. The man that had killed so many people close to Harry, that practically killed Harry himself was finally dead.
Harry was relieved it was over. He fell backward onto the floor, face up, to rest now that his deed was complete. Then, suddenly, lights burst on, blinding Harry as only florescent lights could. He rolled over onto his stomach with his palms covering his eyes in pain.
"SURPRISE!" came the cries of many people, who came out from random places with brightly colored decorations and party supplies. Harry sat up and tried to look around, but his vision was still blurred and his eyes still hurt from the sudden light change. He could only see dark blobs walking toward him and put his arms over his head for protection against what they might try to do.
"Harry!" cried a man's voice! Harry rubbed his eyes a bit and, finally, they returned to normal state. He looked up at the man who seemed oddly familiar.
"What's going on!" Harry asked in a quite demanding tone, considering whom he was talking to, though he still had no idea. Harry looked around some more and noticed some of his friends. There was Hermione, Ron, Neville, Luna, Ginny, and Hagrid, then Harry saw someone he though he'd never see again! Dumbledore was smiling pleasantly at Harry from inside the circle of people that surrounded Harry. He craned his neck to the left to look at the others: some Death Eaters, including Draco, his father Lucius, and Snape, were grinning sheepishly at him! What the hell was going on? He flung his head around to the right and there, he couldn't believe his eyes, Harry saw his mum and dad! He wanted to cry in joy, but was too shocked and confused to do anything but look back at the man standing right in front of him who smiled, too. Wait a minute! Harry really did know this stranger in front of him! It was Sirius, looking in much better health and seemingly taller than since before he had died!
Harry's mouth gaped open, trying to say words but his vocal chords were too tight to even make a squeak.
Suddenly, Voldemort's body shot up and let out an ear piercing, maniacal laugh. Harry jumped ten feet up and back. The throng gathered around Harry giggled, laughed, and squealed in enjoyment. Harry looked back up at the new Sirius for an explanation.
Then, out of the blue, Ashton Kutcher ran into the center of the circle.
"Harry," he started to explain, "you've been Punk'd!"
"Whaaa?" was all that Harry could get out.
Everyone in the area burst out laughing even harder then before.
"The past eighteen years of your life have all been a setup! There's no real Voldemort! That's just a robot!" A spark flew from Voldemort's eye. "Everything in your life has been planned! Your parents aren't dead! In fact, no one that you saw die is really dead! Look:" he pointed at a corner of the room they were in, "there's a hidden camera there!" And, in fact, there was a big black piece of equipment fastened to the corner of the room.
Harry stood up as Ashton started laughing and patting Harry on the back. Rage was building up inside Harry and he wanted to hurt something, so he took his wand and stabbed it into Ashton's left eye! Ashton screamed in pain but soon lay dead on the floor.
Harry exited and was never seen again.
And Ashton was dead.
And everyone else led the rest of their lives in peace and success, always remembering the fun they had creating and pulling off such a huge stunt and hoping to do it again sometime, though they were a bit sad that Harry went and stabbed Ashton in the eye, but they got over it (and quite quickly I might add).