Remember, your child will grow up. Almost like putting up sections cut out from wall paper. Wall paper is a great tool for putting up a new look with out paint. Cutting pieces of wall paper and placing it on the wall in arrangements can be rewarding and new too. For children who love to draw on the walls try putting up a hearty border and under that border, white washable wall paper.
Rubber stamps are another tool too.
You can manipulate any color ink on a white background or a white border set aside for designing. You can decorate with rubber stamps around light switches, outlets, door handles, doors, any where. Textured walls and ceilings. You can use these as borders too. Paint the textured look think and white, then when it dries, go over it again with a paint brush in another color.