Some of my students are working on box sculptures, one of my (& their) favorite open-ended art projects. First, kids decide what they're going to make and then they join boxes sturdily with masking tape and glue, making sure to tape over any gaps or holes. Choice of subject matter is vast. Consider animals, people, vehicles, fantasy creatures or inanimate objects. One of my students made a garden gnome with a birdbath, and another made an awesome sky diver with a parachute! Some of my students have kept their box sculptures for years, and have even used them as coffee tables!
The next step is to brush artist's gesso onto all surfaces of the sculpture & allow to dry. Then paint the sculpture with tempera or acrylics, using realistic or fantasy colors. When the paint is dry, any collage materials, such as buttons, feathers, fabric or pipe cleaners can be glued on for decoration and detail. The more color and detail, the merrier, so even paint markers can be used to add lines or dots.
Try to save clean, dry boxes and cardboard tubes at home to have available for this project. It's a great way to recycle boxes, and box sculpture is a wonderful creative project for kids to make independently.