As an ancient alicorn trapped inside a library, Princess Twilight spent many a century dreaming of being rescued from her prison. Now, finding herself in an entirely new Equestria, she realizes she'd never planned for somepony to actually succeed...
Rarity expected a temporary job as Canterlot Castle's royal tailor to be easy. She could handle the glitz and glam, dealing with nobles, and even the string of suitors vying for her heart. She just hadn't expected Princess Celestia to be one of them.
Humanity's space exploration ultimately took the form of billions of identical probes, capable of building anything (including astronauts themselves) upon arrival at their destinations. One lands in Equestria. Things go downhill from there.