I play Contraband with my GSs. Briefly, it is a very old fashioned card game where players have to 'declare' what they have in their hand of cards but they don't have to show them to the person designated as Customs Officer so they can lie and the CO can either let them through or challenge them, an incorrect challenge costs the CO £200. The cards include several nylons, brandies, perfumes etc and one card with the Crown Jewels. Most cards are baggage for which there is no charge.
There is more to it than that but it is a good, old fashioned mixture of skill and luck.