Pinkie Pie taking on the parasprites is one of my favorite moments in MLP:FiM. Everypony thinks she's just being crazy the whole episode, and then she breaks in with the Parasprite Polka and saves the day.
If you run into parasprite problems, then make sure you take a look at the sheet music Der Mann shared with us. With help from vijey5, GolD Roger, and L'asian Jesus, Der Mann came up with a great resource for this song.
Thanks for sharing, Der Mann!