Bunny Day comes just once a year in Animal Crossing: City Folk, and with it comes Zipper T. Bunny. Zipper's hidden a bunch of special eggs all around town, and your goal is to find them all. Dig them up with your shovel and see what's inside. If you find any bunny foil, trade it with Zipper and he'll give you a prize in return.
Zipper may seem like a jumpy, energetic bunny, but, underneath that fluffy bunny costume, he's a lonely old soul, who's job is to just hide eggs around town. When you approach him, he may jump about, but once out of sight, with your eyes still on him, he sighs and stands still.