I quote Cristian and think we should be able to use a bit of marketing :-)
"Wiki loves books" and "Wiki loves readings" are great names, for me.
We could start a contest that can grow more and more over the years,
have the help of Wikipedia and so on.
But we have to start somewhere, and I think a real international proofreading contest is the way.
It must be simple, fun, easy.
I suggest the prizes as last year (it.source):
1. first prize for the user who proofreads (aka validates) the highest number of pages. 50 euro
2 second and third prize for user who will be randomly picked. Every user gets a "ticket" for every page validated. More pages he reads, more tickets he gets, more probable is that he will win.
I would suggest "low" prizes for the challenge.
If rewards are too high, people will be more likely to cheat, and we don't want that. If the prizes are reasonably small, it's more fun, it feels like a game.
One thing that was tremendously effective last year is to ask our fellow wikipedian for the use of the sitenotice. It's just for a week, and drives many people into our page.