Spike and Pinkie were going about their chores as normal. It was their duty, along with everypony else, to move the rocks from the south field to the east field. The twins were behind on their work so they had to stay outside longer. Igneous had just closed the door to the house when it happened. A loud boom caused both Spike and Pinkie to turn and look for the source when they were blown back a little by a strong wind. Pinkie's hair fluffed up and they both saw the most amazing thing, a horizontal, expanding, rainbow ring. They both broke into super-wide grins.
"Wow!" Pinkie exclaimed. "Spike did you see that!?"
"I did!" Spike yelled excitedly, "That! Was! Awesome!"
"We have to show this to everypony!" Pinkie yelled, just as the rainbow dissipated. "Oh....well, we'll have to...show them something else that's just as awesome and fun!"
"But what?" they both pondered. After a moment of thinking, Pinkie smacked her own hoof and declared loudly to her brother, "Let's throw the biggest, most amazing surprise party ever!"
"Yeah!" Spike agreed and together they ran off to the storage silo.
-the next morning-
The Pie family was just leaving the house.
"We better harvest the rocks from the south field," Igneous said, but he and the others stopped when they heard the sound of music.
"Pinkamena Diane Pie, Spike Boulder Pie, is that you?" Cloudy called.
Pinkie's head popped out of the silo door. "Mom, I need you, Dad, and the sisters to come in here quick!" Pinkie yelled as she ran back inside. Cloudy and Igneous looked at each other in confusion, then entered the silo to find decorations, cake, punch, and balloons. Pinkie jumped out from under the tablecloth and Spike floated overhead with the help of some balloons
"Surprise!" They both yelled.
"You like it?" Spike asked.
"It's called a party!!" After a few seconds of looking at what was in front of them, the family's faces all broke out in huge grins. After a few more seconds everypony was partying.
Spike suddenly gasped, "Pinkie! Your flank!" Pinkie looked down and spied a mark of three balloons; 2 blue and 1 yellow.
"Gasp!" Pinkie cried out, choosing to say gasp over actually gasping, "I have a Cutie Mark!" And so on the party went, from dusk until dawn.
Pinkie and Spike never wanted it to stop.