Actually, I have 2 ideas that I was involved in as a child, and have never seen them duplicated.    1.  My mom threw a "come as your Grandma" party for me when I was about 9. As silly as I thought it was at the time, and thought none of my friends would ever speak to me again, every girl (about 15) showed up dressed like an old woman.  It was hilarious and we had a wonderful time at the tea party my mom had put together!   2. This is an idea for a reverse surprise party.  You send invitations to your child's friends parents announcing that your child is giving a surprise party for all of their friends.  Then, the morning of the party, you go house to house and pick up your children's friends, and try to get there before they wake up. You then take them in their pajamas, on to the next house. Once you have collected all of the children in their pajamas, you take them either back to your house for breakfast, or you can really embarrass them and take them out for breakfast, and the birthday party follow after. One of the parties I was involved in like this, the mother hired a trolley to pick up all of the girls.  Very fun and exciting!!