Can a prize promotion be run that is based on skill?
Yes, but it should be ensured that the winner is selected only on the basis of his physical or intellectual skill, not on chance (not even partly). The skill involved should be sufficiently convincing (e.g. not: What is your name?, which requires no effort). There is no need to involve an external jury to assess the entries made in this respect.
Specific rules may apply in cases where the winner is selected on the basis of both skill and an element of chance (see Prize Draws section).