Crossover with The Dresden Files.
Pinkie Pie randomly shows up at the apartment of one Harry Dresden, Wizard-for-hire. And then she does ... whatever it is that Pinkie Pie always does. Madness ensues as Equestria's craziest Party Pony inflicts herself on everyone's favorite cynical smartass of a wizard.
My Little Denarians is the sequel to this story.
This fic now has a dramatic reading courtesy of Comma Kazie and Lisa M.