A rope bracelet - reminds me of making friendship bracelets back in the day. My right second toe used to go numb because I'd hook the end of the bracelet over it, and then knot embroidery floss for HOURS.
Homemade retractable bathtub crayons and/or watercolor crayons from De tout et de rien. I love bathtub crayons as an adult cause I do all my think in the bathtub. Our tub walls always have math equations all over them.
Materials: KNUFF Magazine file set I have found this idea on one czech website, Napadyproanicku. You need three pieces of Knuff magazine files, wooden blocks, hot glue gun. Magazine files and block (Diy Furniture Redo)