Pinatas are a lot of fun to make and can be prepared quite a while ahead of the party (though at times between cakes, invitations, decorations and the zillion other things you'll need to do, it's ok to break down and buy one from your local party store*grin*.

General Paper Mache Instructions

Bird Pinata

Bat Pinata

Dinosaur Egg Pinata

Dora the Explorer  -- round pinata (punch ball from the dollar store) with black crepe paper hair and painted on features -- check out the Rock Crusher Pinata for specifics on how to make a round pinata

Fish Pinata

Frog Pinata

Rock Crusher Pinata (Construction Theme)

Pikachu (Pokemon) Pinata

Spider Pinata -- great for Halloween or Spiderman party

Super Simple Pinata -- this is the easiest (and least messy) version of a pinata I know.  It's great for groups of kids.

Gigi offered this suggestion for those making a Pinata...
"If you are making a Pinata the night before you can help dry it quickly by using
 a dehumidifier.  It will be dry in no time!"

When we have a birthday party pinata, here's what we do with our guests to make the stick to whack it with!

As we're opening gifts, we let each child who brought something add some of their wrapping material to the stick.

We use a cardboard tube from gift wrap as the base:

•  Each child can wrap some of the torn off tissue paper or gift wrap onto the tube, taping it on tightly.
• Or they can add bows and ribbons from the gifts they brought to one of the ends of the tube.  We do this by tying the bows or ribbons to one end of a string and threading it through the tube.  We then tie more bows and ribbons to the other end which keeps it from pulling back out the tube (you can also add a little tape if you're worried)
• If you have a lot of party guests, you can make 2 or 3 sticks.
• We use our decorated sticks to beat our home made pinatas (home made pinatas usually break fairly easy depending on how many layers of paper mache you use so these cardboard sticks work much better than a wooden one...  And they're safer if someone accidentally gets hit).

Hang the pinata up from the ceiling. Each child gets a turn trying to break the pinata.  Blindfold the child and give them a stick (a broom handle works well) -- make sure all the other children stand WELL back from the swinging!  Turn the child around in a circle 2 or 3 times and point him or her in the direction of the pinata.  The child gets to swing the stick 2 or 3 times.

Then another child gets a turn.  When someone breaks the pinata, all the children get to gather the goodies.  You might want to prewrap the goodies in bags so they don't get paper mache on them and so that each child gets and equal share -- this is especially useful when the children are of various ages.

TIP:

• I use skipping ropes, to rope off a small circle inside a large circle.
• The stick (and whoever is using it) stays inside the small circle.  When the person's done using it, they have to put the stick down inside the small circle before they go back to the audience.
• The audience stays outside the large circle
• At most parties, remembering the rules of the circles becomes as much of a game for the kids as whacking the pinata.