This is a fun card for many occasions, inspired by this Paper Cub card http://www.thepapercub.com/portfolio/pinata-birthday/
It's pretty simple to make, but rather time consuming because you have to cut so many tiny fringes.

First, let's gather our supplies:
>>> a sheet of white card stock
>>> different colors of crepe paper streamers
>>> a pencil and eraser
>>> a glue stick
>>> scissors
>>> candy (not pictured)
>>> a toothpick (not pictured)
>>> an exacto knife (optional, not pictured)

Step 1: Get Started!

To begin, fold your paper in half (or cut your paper in half and then fold). You can make your card any size you want, just remember that the bigger the card, the more candy you can fit in the pinata. I used half a sheet of white card stock for my card.

Next, sketch out a pinata shape on your card. You want to make the body as large as possible while still maintaining a recognizable shape. Your pinata should be more on the right side of your card then the center, so you still have room to attach the 'bat'.

Draw a rectangle shape in the body of your pinata, going almost all the way to the edges. You could also just trace the candy you plan on putting in the pinata.

Step 2: Start Decorating

Cut out the rectangle in the middle of the pinata using scissors of an exacto knife.

Cut small strips of crepe paper the length of your pinata drawing. Cut small fringes in them (slits that go about 3/4 across the strip, width wise).

Start gluing your fringes onto your pinata drawing, starting at the bottom. Before you get to the hole in the body, cut a piece of crepe paper to cover it and glue it on. (see pictures)

Continue adding crepe paper fringing until you get to the top.

Step 3: Fill It Up!

Open your card and place the candy on top of the hole. An Andes mint fit perfectly in my card. You could also put in some confetti if you wish.

Take one or two strips of crepe paper and glue them over your candy/hole to keep the candy from falling out (obviously).

Now close you card again so you can add the final touches.

You can take a piece of crepe paper (or washi tape if you have any) and use it to glue on the toothpick. The toothpick is the 'bat' used for bashing open the pinata.
I also wrote PARTY! on the front of my card with matching colored markers.

TADA! You are finished! Sorry there are no pictures of it being opened, as I actually gave this card to someone for their birthday.