Book trailers, actually.
I've been discussing this with a young lady who makes films. She had a hand in one for Random House and one of their 'Best Seller' authors. The numbers she gave me weren't as big as I would have expected, but now I have to think this through carefully. Which book to do this for? What aspects of the story do I want the trailer to reflect? How will I pay for it?
It needs a lot of very careful consideration I think.