A/N: I found this lurking around on my hardrive, and after a little tweaking, I thought I might as well put it up here, rather than just leave it to collect dust. This was inspired by a comic on deviantART, which I wish I could put a link to here, but... well, yeah.

So, I know this ought to have been put up on the first of April, but I totally forgot I had it, and I'm not gonna wait another year. So, it's nearly two weeks late, but there you go.

Also, I suck at coming up with pranks, so I apologise if the pranks seem a little lacklustre compared to Fred and George's usual flair.

Woken by the sun shining in through the thin fabric of the curtains, George rolled over and grinned when he saw his brother was awake. Head resting on the pillow beside George's, Fred matched the grin on his twin's face with an identical one, and they didn't need words to communicate their excitement for the day. "Freddie! Georgie! Are you two up?" Their mother called through the door, and the twins snickered silently to each other.

"Muuum!" George whined as Fred hid himself under the bed.

The door opened and Molly stuck her head inside. "Georgie?" She called, looking at the small boy curled up in the bed, his face buried in his pillow.

"I'm Fred." George corrected her with a miserable little sniffle.

"Sorry, Freddie." Molly said with a little wince. She sat on the bed next to him and put a hand on his back. "Are you ok, Freddie?"

"Stummy hurts." George mumbled, doing his best to keep his voice petulant and miserable.

Molly immediately turned him over gently so she could check his temperature and indulge in other motherly fussing. "Oh, Freddie. You poor boy. And on today of all days!" George couldn't help but raise his eyebrows at his mother. It wasn't like her to remember a day like today. She didn't really seem to condone the day, although, she had joined in last year, he remembered. Molly saw his raised eyebrows, and took it the wrong way. "Really, Freddie, did you think I'd forgotten?" She said softly, tutting warmly. She leaned down to press a kiss on his forehead. "Silly boy."

"I didn't think you'd forgotten." George mumbled, looking away.

Molly chuckled and drew out her wand, casting a sensory charm over 'Fred'. "Well, nothing seems to be wrong, dear." She mused, frowning. "I'll give you something to ease the pain and we'll see if it goes away on its own, yeah?"

"Ok." George agreed with an adorable little pout, pulling the covers up to his nose.

"Let me just wake your brother, then I'll go fetch the-" Molly began as she was getting up, but she stopped when she saw that the other bed in the room was empty. "Fred, where's George?" She asked in a perfectly calm voice that George knew was her 'I'm-almost-panicking' voice.

Blinking innocently, George sat up and looked over at the other, not-slept-in bed. "I- I don't know." He said, doing his best to make his voice sound frightened and uncertain. Molly's eyes went wide and she looked around the room, and seeing no 'George', she bustled out of the room, calling for George. Immediately, Fred slipped out from under George's bed, paused only long enough to give George a quick high-five, then darted to the window and slipped out of it, climbing down the rough brickwork to the kitchen door below.

George waited, grinning. Just as the tension was beginning to get too much, he heard his mother scream. "Georgie! How did you get down here?" Snickering to himself, George clambered out of his bed quickly, grabbed the bag of supplies that he had Fred had prepared the day before and darted out of the door, heading for the bathroom. Once there, he switched the Anti-Pain Potion for a concoction of his and Fred's own design. It was utterly harmless, except it turned the consumer's skin neon green. He also, while he was there, switched the talcum powder for itching powder, and the mouthwash for something that would stain teeth blue (an interesting muggle invention he and Fred had found in the corner shop in Ottery St. Catchpole). Last of all, he placed a large fake spider in the corner of the shower.

He left the bathroom just in time to duck behind a corner as Percy stumbled out of his room and into the bathroom, looking half asleep and dead on his feet, in his white and red striped pyjamas. As the bathroom door shut, George scurried down the hallway and into Percy's room. He replaced his brothers glasses with some not too shabby replicas, if he did say so himself, that had only plain glass in them. He also switched round his books, messing up the painstaking reference system that Percy had come up with. He left his brothers room just as the door to the bathroom opened and Percy trooped out.

Making sure to hide himself, George watched as Percy walked towards his room. Then Percy yawned, and George grinned. His brother's teeth were a bright, rich blue. Once Percy was back in his room, George hurried back to his own and hid the bag before diving under his covers. Just in time, as Molly bustled into the room not a moment later with the bottle of 'Anti-Pain Potion' in her hand and a very cheerful looking Fred in tow. "Here you go, Freddie." Molly said sweetly, pouring a lid-full of the potion and holding out to George.

George took it and drank, pulling a face at the non-existent nasty flavour. "Ick." He said, sticking his tongue out as he passed the lid back to his mother.

"You feel better now, though, don't you, Freddie?" Molly asked sweetly.

"Mm… a little…" George said with an uncertain face. All of a sudden, he saw his skin fading to a nice lime green. "Yeah, I feel loads better!" He said chirpily, even as his mother's face went from sweet to horrified.

"FREDDIE!" Molly gasped. "You're green!"

"Huh?" George looked down at himself and pretended to be surprised. "I am as well!" He gasped in shock. He looked up and met Fred's eyes. They grinned at the same moment. "COOL!" They both said in unison.

"Oh, this can't be good!" Molly fretted, checking George's temperature again.

"But I feel fine." George said with sweet confusion.

"But you're green, Freddie, dear." Molly said.

"But that's cool." Fred put in, grinning. "I wish I could be green!"

"You'll be able to tell us apart for the day, now, mum!" George added brightly.

Molly frowned. "Well, if you're not back to normal by the end of the day, then-" She said, then nodded fiercely. "-then you're going to St. Mungo's!" She insisted.

"Alright, mum." George said with a pout.

Nodding in satisfaction, Molly smiled at the twins. "Well, why don't you come downstairs for now? We've got a special surprise for you in the living room." She added.

Fred and George exchanged looks. So their mother was going to join in, huh? They thought to each other. Good thing they'd got a jump start on her, then. They nodded eagerly, desperate to see what sort of prank their mother of all people had come up with. Last year had been a surprisingly good prank, but this year they were prepared! Nothing their mother did was going to get the best of them today!

As they stepped into the living room, they were confronted by a large banner that said 'Happy Birthday!' on it, and their family scattered about, grinning at them. "HAPPY BIRTHDAY!" Everyone yelled cheerfully.

Fred and George just stared at them.

They were silent for long enough to cause a measure of concern in the other Weasley's, and they shared a few confused, uncertain looks. "What's wrong?" Arthur asked. "George, why are you green?" He added.

"I'm Fred." George corrected, and Arthur apologised.

"You lot are awful at this!" Fred burst out, scowling.

"Absolutely pathetic." George agreed with a firm nod and a stern look.

Everyone else pretended not to get it, and Charlie even had the nerve to ask "Awful at… what, exactly?" with a confused frown on his face.

George couldn't help but tut at him. It was just bad sportsmanship to continue pretending once you'd been caught. "It's really not that hard, sillies." He pointed out.

"Maybe they just don't have our natural talent, Fred." Fred said consolingly, placing a comforting hand on his twin's shoulder and shaking his head in a sorrowful manner. Now there was utter confusion on the faces of everyone in the room.

"True, true." George agreed, shaking his head as well. "We are gifted." He mused with pride. "But to forget the biggest rule of all!" He added with a slightly over-dramatised gesture. "And to think we were just about willing to admit we were related to you all…" He added with a great sigh of disappointment.

There was a long moment of silence, in which everyone stared at the twins. Then, finally, Arthur pushed his glasses up his nose, coughed and peered at the twins. "What rule?" He asked uncertainly.

Fred and George looked at each other, then at their father, and spoke in unison. "You can't pull the same prank twice!" They announced together.

There was another startled silence. "Prank?" Molly asked, sounding perfectly confused. The twins had to give their family credit, they were much better actors than they'd previously thought. "What prank?" Molly added.

George huffed. "This whole 'birthday' malarkey!" He stated, waving a hand in the air.

"This… isn't a prank." Arthur said, frowning still. "It really is your birthday." He told them, clearly concerned that they'd forgotten.

The twins exchanged another look, and grinned. "Yeah, good one." Fred said with a mocking expression and a slight snort.

"Do you think we don't know it's April Fools Day?" George asked.

"Yeah." Fred agreed. "You pulled this prank last year. We're not gonna fall for it again!"