It was a summer day in Ponyville, and everypony was out enjoying the warm weather. After helping out with her chores at Sugar Cube Corner, Pinkie Pie decided to pay Twilight a visit.
She knocked on the door repeatedly, "Twilight? Twilight, are you home?! Smart-cookie?!"
"Oh, hello, Pinkie." Twilight had answered the door.
"Wanna go have a picnic, or maybe go swimming? Oh, I know! How about a tea party?!" Pinkie Pie exclaimed.
Twilight's ears folded back, and she didn't have an enthusiastic look on her face, "I'm sorry, Pinkie Pie, really...I just can't today. You caught me at a bad time."
Pinkie Pie asked, "Why? I thought you loved hanging out with me. Y-You're not mad at me, are you?"
"No, I'm not, it's just the princesses have summoned me to Canterlot to prepare a royal banquet for the leaders of the other lands. You see, they are having a meeting today. Princess Celestia also requested I'd stay, so they can meet me." Twilight responded to her pink friend.
"Oh...I get it...I guess I'll just go now..." Pinkie Pie sadly said.
Twilight sighed heavily, "Do you want to house-sit for me until I get back? I should return by morning."
Pinkie Pie's eyes lit up, she ran over to her friend, and gave her a giant hug, "Yay! Thanks, Twilight! Don't worry, I'll take superly good care of your house!" She put her hoof up to her forehead to solute.
"I count on it, just please don't destroy anything while I'm away..." Twilight hesitantly remarked.
Pinkie Pie smiled, "Don't worry! I won't let anything bad happen!"
"Alright then...goodbye." Twilight said, walking away.
"See you in a while, crocodile!" Pinkie Pie waved, then went back in, closing the door behind her. She then hummed a song as she dusted her friend's house. After she was done, she sighed, as she was bored. "Ugh...I didn't know house-sitting would be soooo boring!"
Owlicious came along and hooted.
"Oh, hiya, Owlicious! How are you?" Pinkie Pie jumped up and questioned.
"Who." Owlicious replied.
Pinkie Pie giggled, "You, silly!"
"Who?" Owlicious repeated.
"...I can see you can't say anything else. Welp, I'm just gonna go upstairs!" Pinkie Pie bounced up the stairs into Twilight's room. Owlicious flew behind her, suspicious of what she was going to do.
Pinkie gasped, "Whoa! Pretty, shiny...sparkly! Gee, how many inventions can Twilight make?!"
Owlicious gave a warning hoot, but Pinkie Pie ignored him.
"Ohh, what's this?!" Pinkie Pie read the label out-loud on the back of the device, "Time-Travel Clock...Do NOT Touch."
Pinkie Pie laughed, "Oh, silly Twilight! She forgot all about Opposite Day! This means that I CAN touch it!" She threw it around her neck, as it was a necklace with a clock on it. "Hmm...how do you work this thing?" Pinkie saw a red button on the side, and pressed it.
"Huh, nothing is happening." Pinkie Pie said to herself. Then, she began to fade away and she laughed as she was being pulled away through a portal, "Wheeee!!!"
Author's Note
I'm not really one for time-traveling stories, but I think this is pretty hilarious, lol. There is not going to be a sequel to this, as I can't really plan one out. I normally try to write sequels, but this story...not sequel-material. So, I apologize for that, but I hope everypony enjoys the rest of this story! 
(I normally only leave one author's note, since I mainly explain everything I need to in one.)
Pinkie Pie arrived at The Rock Farm after being spit out of the portal.
"Ouchie!" She rubbed the back of her head. "Whoa...this looks just like my old home on The Rock Farm!" Just then, Pinkie Pie gasped, "Wait...I'm a filly again! How...oh...Twilight wasn't lying about Opposite Day, I really shouldn't of touched this...I've gotta find a way back!"
She walked into the barn first, but there were only rocks piled up in separate places. Pinkie Pie saw Maud and her parents harvesting rocks out in the fields.
Pinkie Pie thought to herself, "Hmm...Maud's smart! Maybe she can help me get back home!"
She ran up to Maud and shouted, "Hi, Maud!"
"Um...who are you, exactly?" Maud asked.
"Huh? Maud, it's me! Your little sister, Pinkie Pie!" She smiled.
Maud replied, "It's weird we have the same last name, but I don't have a sister. I just have my pet, Boulder. Also, what is that thing on your mouth?"
"Oh, my smile? Smiling makes everypony feel happy inside!" Pinkie Pie grinned wider.
"What's...a smile?" Maud responded.
Pinkie Pie's ears folded down, "It's...I need to get out of here, goodbye!" She ran off into the distance.
Maud looked at her run away and then muttered to herself, "What a freak, right, Boulder?" Her pet rock fell off her back. "Are you okay?" She asked it, even though she seemed unconcerned.
Pinkie Pie pressed the button again, but this time, the portal took her a thousand years into the future. "Ugh...where am I now? Why do I sound so...old and move slow?" She gasped once more, "Oh, no! I'm an elderly!"
She ran towards The Ponyville Retirement Home, but her legs wouldn't run like they would normally, so she was running about as fast as a tortoise.
When she finally got to the home, she exclaimed, "Rainbow Dash, Rarity, Applejack! I need your help! I took this clock from Twilight, and it sent me back in time! Well...forward now!"
Rainbow Dash nagged, "We're trying to play cards here, go away!"
"Cards? WHO ARE YOU AND WHAT HAVE YOU DONE WITH DASHIE?!" Pinkie Pie shouted.
Rarity asked, "What did she say?" Flinching her ear.
Applejack replied, "She said she found a clock doo-hickey and needs to go home."
"But, this is home." Rainbow Dash said.
"She's just a loonie, Rainbow, just a loonie. Let's go back to drinking our hot tea and play a nice game of cards." Applejack answered.
"Ohh...where's Fluttershy?!" Pinkie Pie ran over to her, but she was knitting. "Fluttershy, I need your help!"
Fluttershy replied, "Where are you? I can't see anything. I'm terribly sorry, but I am blind."
"Blind?! Fluttershy, what are you talking about?!" Pinkie Pie was worried about her friends.
Fluttershy responded, "The question should be, what are you talking about? This is a senior-citizen retirement home...stop acting so insane like a loon and go see a therapist."
Pinkie Pie was speechless, "T-Therapist? I can't take this anymore!" She pressed the button, this time it took her to a blue space, where there was a path made of pure stars.
"Where am I? What is this place?! Well...at least I didn't age again..." Pinkie Pie said.
Princess Luna walked up, "Greetings, Pinkimena Diane Pie."
"Luna?! Boy, am I glad to see you! That means this was all just a dream!" Pinkie Pie exclaimed happily.
Princess Luna replied, "Actually, no, this is very much reality. Although...this dream...is about to become..." Luna morphed into Nightmare Moon, "A nightmare! Muhahahahahahaha!!!"
Pinkie Pie screamed, "WHAT KIND OF WHACKED UP PLACE IS THIS?!?!?!" She ran away screaming, "No! No, don't hurt me! No! WHAT?!?! NO WHIPPED CREAM WITH THE CHOCOLATE MILK?!?! YOU EVIL, EVIL WITCH! YOU'RE A MONSTER!!! A MONSTER!!!"
Twilight's voice echoed faintly, "Pinkie Pie...Pinkie Pie...Pinkie!"
Pinkie Pie woke up, "H-Hmm?"
Rainbow Dash started laughing on her back, "We really got you good, Pink!"
"W-What's going on? I don't get it..." Pinkie Pie said.
Discord was in the room was well, and replied, "I didn't take Twilight as a prankster, but I gotta say, she planned this out very well!" He laughed.
Twilight looked at Pinkie and added on, "I knew you would marvel at my inventions, and I didn't want you to wind up in any real trouble. That's why Spike here stayed behind with Owluicious and a walkie-talkie. Discord used his magic to make you a filly, an old mare, and change the different time-periods. It was all a lesson to teach you not to take other ponies things without permission first."
"Ohhh, I get it now!" She laughed a bit, then paused, "Hey!"
Applejack replied, "Ya gonna be more honest now?"
Pinkie Pie responded, "Yeah, but I just don't get why I had to learn this lesson."
"You took Rarity's comb and forgot to return it, you took Applejack's spare hat without asking, and you tried to take my time-traveling device. We wanted to stop you before it got too out of hoof." Twilight explained.
"Oh, well...I guess I can say lesson taught! I promise I won't ever take anypony's stuff ever again without asking!" Pinkie Pie smiled.
"Pinkie Promise?" Fluttershy asked.
Pinkie Pie grinned, "Cross my heart and hope to fly, stick a cupcake in my eye!" They all laughed, and forgave Pinkie for her wrong doings, and Pinkie Pie also returned everything she had either took or accidentally had to the right pony.
THE END
Author's Note
I know it isn't the best story, but I tried. It seems pretty awesome to me for being my first story!
And remember, don't take things that don't belong to you! 
