I agree with Samsterdam. If you made UE4’s curriculum about taking what they’ve learned and making something original or to a set of guidelines, you could offer prizes to the best submissions…
The most notable example of this was a multi- contest called Dominanace War. Albeit it might be a struggle doing something like that single-handed, however, ZBrushCentral also do smaller contests where the winner and runners receive a painted statue of their artwork.