Theme: Twin Party
This kind of a party can be done both outdoors and indoors.
In a twin party two people have to look the same and come in pairs. Sometimes it is not possible to look identical to each other but as far as possible try to be the same.Costume
Ask two children to come dressed in similar clothing. It need not be identical but in some way matching. For instance they can wear blue jeans and white T-Shirt or the same colour frock. They can have the same hairstyle as well.
Starting with the curtains in the room you can arrange them in such a way that two identical looking ones are together. Things like posters, balloons and streamers can be arranged in pairs.
Since it is impractical to have a variety of chairs and crockery, you can use accessories like ribbons to make two things look alike. For example, buy ribbons of different colours and tie them around the spoons. Two chairs can have balloons of the same colour.
You can give identical return gifts to the children who are dressed as twins.
Have the children walk into the room with their twin. You can play any song on which they can dance and ask them to do a few dancing steps.