You spend 2 hours hanging things from the ceiling. This weekend we finally hung the planets made from yarn balls from Cash's birthday(June) from the kids ceiling, and part of the 1000 origami cranes I made for Yuliya's birthday(March) from the ceiling in other parts of the house. Here are a few pictures, they are so much more beautiful in person. The cranes can detect the smallest movements in what you thought was still air and use it to dance and cast pretty shadows on the walls.
Planets from the kids ceiling in order, the sun is in front of the closet, neptune is dark blue.
These are the cranes in a corner in my room, I'm completely impressed with how great they look underlit :)