I think 12-yr old's would love Karaoke. I believe you can rent the equipment.
Perhaps a large TV playing music videos or for playing video games.
You can do something fun with the food like having them make their own ice cream sundaes...ice cream with many different toppings.
You can make a mock photo booth.
You can have someone go around with a video and get birthday wishes from guests.
Good luck! Hope this helps!
Cupcake decorating party, spa day, disco party, etc... Not really sure:P
