Jimlad - on my last Westbound Gatwick/Orlando with Virgin Atlantic they not only threatened a quiz on the safety video - they DID one (and I won a bottle of Champagne for it).
They simply asked the pax, "How many emergency exits are there on this Boeing 747-400?".
Most of the peeps counted the exit signs on the ceiling, five, the brighter ones then doubled it to get ten.
NOT ONE of the downstairs SLF thought about the upper deck doors - and presumably, not one had the sense to look at the safety card in the seat pocket.
The crew also ran a drawing competition for the kids - asked them to draw "The Captain" (but they had to make it up as they'd never seen him.