You can reinforce some previously taught vocabulary whilst they make something that they can take home and proudly show their parents. Parents also can have some insight what topic you are on in your ESL class. 
So at the zoo animals topic your young kids can make this paper lion mask. Boys will specially love making a fierce, fierce lion!!! 
What you will need:
Old newspapers (to cover the tables)
Orange or yellow cardboard paper 
or white paper and yellow paint
Brown tissue paper
Brown plasticine
Gluesticks
Black felt-tip pen
Scissors