Make a personalised advent calendar that can be used year after year. Paint 24 empty matchboxes, number them and glue together upright, six wide by four high, to form a rectangle. Cut pieces of balsa wood for the base and sides. Cut two matching triangles from the wood, with one edge the same width as the house, then use two more pieces of wood to create the roof – add a chimney if you like. Attach everything together using a glue gun. Fill the matchboxes with treats.