The Heide Museum of Modern Art in Heidelberg, Victoria is currently running a clay challenge.
You need to use clay,
or plasticine, or playdoh and make an artwork inspired by one of the clay pieces from the Heide Collection.
You photograph your work and then email it to Heide.
The link below will take you to the page on their website which has photos of their claywork to inspire you.
There is a category for under 18 claywork entries and over 18 claywork entries.
I think the challenge only goes until the end of May so you will have to check the details for dates on their website.
Good luck with your entry!