I've had the privilege in the past of devising, writing, designing and illustrating competitions, installations and comics directly for child friendly events without the filter of mums. This gave me the license to appeal directly to what I know children really enjoy. I was also able to measure if I had got it right through observing how the products were used. Not only did I see children engrossed and enjoying what I had made but also none of it appeared in the bins around the event sites. Lots of other promotional materials did.
The examples here are made more recently and are intended to pass the examination of most mums.