If you give a tween a party she'll want to do something big to celebrate turning two digits.
Then she thinks about what bathing suit and other things she'll need for a pool.
When she's looking through pool stuff she remembers her American girl doll has a bathing suit. Since her doll has a suit she decides she wants all of her friends to bring their dolls. Then she decides all the dolls will go on a trip together.
If the dolls are going on a trip they will need suitcases.
When you're at the store looking for tiny suitcases she realizes they could make a lot of other fun things for the dolls too.
Then on the week before the party you realize they might get bored, so they might want to do something else like paint their nails with starfish.
And while you are thinking of the party you realize you need cake, but you are tired of cake because you've already had 2 other cakes in the past week. So you think of something inventive and chic like faux sushi. Then you realize you are not Martha Stewart and your sushi doesn't look that cool, so you buy some twinkies and candy fish so they can make different faux sushi. But they don't want to make sushi they just want to eat the twinkies and candy fish.
Then they get sort of bored of playing with dolls and decide to put the new gifts to good use. So they make scented body mist. Then they play drawing games. Then they judge X factor contestants, and then they are tired.
But when they wake up they want breakfast. Then they see chocolate Belgian waffles. Then the breakfast buffet supervisor tells them she has never seen a kid finish the entire waffle. Natalie and Mary Beth see that as a challenge, and they take those waffles down.
Then they have chocolate waffle energy and decide to jump on the beds until they hear a knock at the door.
Then they are all so tired from the excitement, but when they are rested they will want to get together again. And if they get together again they will all want to have...a party.