Harry Potter stared at the monsterous scene that befell his eyes that morning at the breakfast table. it was Dudley's birthday and, as a treat, Aunt Petunia gave Dudley an all-you-can-eat breakfast buffet. Unfortunately, all-you-can-eat meant cleaning the house of everything edible for Dudley; he was trying to wolf down several plates of bacon and eggs, devour mountains of toast, cram hash browns in his mouth and guzzle down orange juice at the same time. The sight was sickening. harry tried not to throw up in his tiny bowl of cereal.
"And when you're done," said Aunt Petunia, sticking her head out of the kitchen, "I have a special birthday cake just for my Duddykins to eat!"
"Oh goody, more food for Dudley to stuff his face with" muttered harry under his breath.
Dudley glared at Harry.
"What was that, Potter?" said Dudley, through a mouthful of toast.
"Nothing" replied Harry, feeling a bit queasy.
Dudley shruged and went back to eating.
After a few moments of eating, Dudley looked up from his plates with a look of fright, which was quickly replaced with a disturbing sick look.
Harry prepared to dive under the table when Dudley gave an almighty 'BURP' and continued eating.
Harry winced.
"Is my Duddykins ready for his birthday cake?" sang Aunt Petunia, sailing into the room carrying a huge silver platter holding one large chocolate cake.
"Almost" replied Dudley, finishing off the last rasher of bacon.
"Here you go, Duddy" said Aunt Petunia, placing the platter right between Harry and Dudley.
Harry stared enviously at the cake, but he knew if he so much as ate one tiny bit of the icing, it was back to the cupboard under the stairs for the rest of the summer.
Just then, Uncle Vernon came in through the kitchen door, back from test driving the new car.
"Ah yes," he said gleefully, eyeing the humungous cake "Happy Birthday Dudley! Do you think I could have a slice?"
"I don't think so dad - "
But Harry wasn't paying attention to what the Dursleys were saying, he was more interested in what had come through the door after Uncle Vernon that no one seemed to notice.
Four house elves (from Hogwarts no doubt) were looking at Harry in awe. When they saw Harry looking at them, they all stumbled back and bowed. Two of them put their fingers to their lips and the other two pointed to Dudley.
Dudley was still arguing with Uncle Vernon about the cake, when one of the house elves leaped upon the table and cleared his throat.
The Dursleys seemed to have frozen at the sight of the elf.

House elf 1: Oompa, Loompa, doom-pa-dee-do
I have a perfect puzzle for you
Oompa, Loompa, doom-pa-dee-dee
If you are wise, you'll listen to me

At this the rest of the House elves jumped on the table and started bobbing up and down.

House elf 2: What do you get when you guzzle down sweets?
Eating as much as an elephant eats?

House elf 3: What are you at getting terribly fat?
What do you think will come of that?

House elf 4: I don't like the look of it

House elves: Oompa, Loompa, doom-pa-dee-da
If you're not greedy, you will go far
You will live in happiness too
Like the Oompa Loompa doom-pa-dee-do

Uncle Vernon unfroze first and grabbed the nearest cooking utensil, which happened to be a wooden spoon and whacking the house elves off the table.
Aunt Petunia reached for the broom and attempted to sweep all the house elves out the door, but they just kept on coming back.
Dudley was encouraging his parents and waving his fork around in the air.
Harry was just watching all the pandemonium around him, trying not to laugh, but then realised that the Dursleys would think it was all his idea and then he would be put back into the cupboard.
"erm...excuse me?" said Harry tidmidly.
The house elves stopped moving, and Aunt Petunia sucessfully sent one flying out the kitchen door.
"I - I think you should go now...back to Hogwarts - all of you!"
All of the house elves turned to face Harry (the house elf that Aunt Petunia got rid of walked dejectedly into the room, rubbing it's head) they all clicked their fingers and were gone in an instant.
Uncle Vernon then advanced on Harry.
"YOU!" He roared, a vein pulsing in his temple.
"It wasn't me!" Harry tried to reason
"Get into the cupboard! NOW!"
It was no good arguing, Harry shuffled over to the cupboard and slammed the door sulkily.
"Aww crap!" cursed Harry "I forgot to get the rest of my stuff!"