My first thought was that the winner could try to sell the shed if they didn't want it - or perhaps even offer it as a prize in a competition they might run themselves.
But to get people talking about it, what would you add to the shed prize? I think that men tend to hide in sheds, don't they? So maybe something very manly like cigars and a good book? (I've thought of other things but it's probably best not to suggest them here.

)