((Prompt: Twilight Sparkle in a band.))
“Come on, AJ!” Rainbow Dash waved her forelegs in the air emphatically. “You said you were coming!”
Applejack sighed, tugging the gate shut. “That was before one of the pigs decided to go missin',” she said. “I can't go to some concert with a sow runnin' loose out there.”
“This isn't just 'some concert.' Do I need to repeat myself?” Rainbow hovered above Applejack, her wingbeats blowing the farmer's hair in her face. “Twilight Sparkle. In a band. The pig can wait, AJ. You can't miss this!”
Applejack tapped her hoof on the fence. There was a mess of prints in the mud; it was going to take her all night to track down where the missing sow was. “I don't know, Dash. You know I wanna go show Twi my support an' all, but...”
“Look,” said Rainbow. “Just come see the opening act, and then I'll help you look for your pig. With me out there looking, we'll find her in like, a minute tops.”
Applejack chewed her lip. “Just the openin' act?”
“Yeah.”
“And when that's over, no balk-talk when I drag you out of there?”
Rainbow pressed her hoof to her chest. “I swear on Hurricane's feathers.”
Applejack glanced at the pig-pen. The opening act wouldn't take more than five minutes. A pig couldn't get much more lost than it already was in that time, and having Rainbow for an eye in the sky would really help. “...Okay, fine. Just the openin' act, though.”
“Yes! Come on, it's gonna be awesome!”
Rainbow and Applejack arrived not long before the concert started. They only just found seats when the lights went dark. In the pitch black on stage, all they could see was a single guitar pick, suspended in a magenta aura. The pick moved, and a guitar chord rang through the amplifiers. Stage lights lit up to reveal Twilight Sparkle with a sleek guitar strapped to her. The crowd cheered.
Her horn glowed, and a second chord played from her instrument. Joining her this time was a steady bass line. More stage lights slowly illuminated Princess Celestia, a pair of reflective sunglasses over her eyes as she played a bass guitar.
Next, drums joined in, pounding out a lively beat. Again, stage lights flipped on, but this time, one of the stage-hooves must have misaligned the light, because only the drum-set was visible, leaving the drummer still shrouded in darkness.
The keyboard was the next to light up. Princess Cadance stood behind a crystal keyboard, jamming out a melody with both her hooves and her magic.
Everypony in the audience jumped as the vocalist spoke up. “ART THOU ALL PREPARED TO ENJOY THINESELVES?” No one needed the stage lights to tell them it was Princess Luna. She had no microphone, just her voice and a ridiculous costume that would have been at home among the costumes the Cutie Mark Crusaders had worn once at their talent show. “WE HOPE THOU ART PREPARED, FOR TONIGHT WE INTEND TO SOCK THY ROCKS OFF!” The ponies in the audience glanced at one another, puzzled.
Twilight whispered something to her. Luna nodded. “BY THIS, WE OF COURSE MEAN TO ROCK THY SOCKS OFF!” The crowd cheered again. “WE ARE THE PRINCESSES OF EQUESTRIA!”
With this, the band launched into their first song. Musically speaking, they weren't all that great, being statesmares rather than musicians, but they made up for any shortfall of talent with their enthusiasm and the sheer spectacle of seeing the leaders of Equestria rocking out on stage in front of everypony.
Still, Applejack wondered who the drummer could possibly be. There were only four princesses in Equestria, as far as she knew, and she couldn't begin to guess who would fill the fifth position. Shining Armor, maybe? He was a prince, that was close.
Finally, one of the stage-hooves got up to the scaffolding and fixed the light, revealing the fifth member of the band at last. Applejack laughed. That certainly explained a few things.
Behind the drumset, bashing the high-hat with both drumsticks clenched in her mouth, was Applejack's lost pig, Princess.