For a quick change in the nursery, try hanging different mobiles every few months. We like this beautiful homemade Crane Mobile.
From concept to finished product, Jordan Ferney makes the process look simple. Start with a two wire hangers and cut into pieces. Use string or fishing wire to attach the wire pieces to each other and the cranes to the wire.
The fun part is deciding what you want to hang from the mobile. Make your own origami cranes or something else lightweight and colorful to look at.