Secret Stocking Surpriser is an old Earth Pony tradition of exchanging names to pick out a gift of some sort for the pony in question. On her first Hearth's Warming in Ponyville, Twilight receives Rarity's name from the hat; unfortunately her request "something creative", proves to be surprisingly difficult for Twilight. But she isn't about to give up!
Hopefully, Rarity will like her present.