“No,” Twilight said with the finality of Judgment Day and Ragnarok combined and tripled. “Eventually there’s nopony left at the party. It’s over. There is no more party.”

Pinkie Pie is suddenly forced to confront the inevitable (albeit distant) end of all things, and does so about as well as you'd expect.

Disclaimer: I wrote this in an hour. It doesn't reflect the overall quality of my work, unless you loved it, in which case it absolutely does.