Do a Google search on crafts to do with door hangers, and you'll get lots of variations on the idea above. The Kids To-Do List door hanger. The idea is simple, but brilliant. Decorate the hanger, and for this you could use nail varnish. The glossy, sparkly sort probably works quite well. I've not tried this particular craft before, but I've used nail varnish on plastic before and it works well.