Ever noticed that small magnets are hard to get off the fridge and don't hold more than one piece of paper?
These are some examples of my answer to the school artwork display dilemma.
They have an MDF base and each have 3 strip magnets on the back. They are also rather large - 8cm or there abouts. They hold up everything and make the fridge a much cheerier place :)
These three and a couple of others are available in my madeit shop.