We have a bonus collecting system called Mnogo.ru. If you buy with their partners, you receive virtual bonuses you can convert to gifts (provided by partners). The more you collect the more you can get. I use this occasionaly collecting bonuses for buying books with boffo.ru and paying for mobile services and transform them into aeroflot miles to get free ticket.
So, Mnogo.ru has a promotional quizes. You can pass it, receive 20-50 bonuses (the prizes cost more - 800 bonuses for DVD, 1050 bonuses for a jar of coffee)and if you pass it successfully, you can try to get a prize from a partner. So, typical staff - answering simple questionary, you get your bonuses and think for a couple of times about Mnogo.ru itself and its partner.
But let's look deeply. The questions are posted in a way you can easily get an answer (with a link provided to a site you can check info). And that is a great trick - if you can easily increase your chances for grand-prix, you most probably will go for it and check. And get more information about the company.
E.g. What is the price for a model XXX (link to a model)? Of course, you will realize that the price is low and will have more incentives to buy the product.
Or: what is the color of a t-shirt XXX (item nr) at a website (link). You will go, see a t-shirt and may be continue browsing the catalog.
And all it for 2.5% of a DVD!!!
I like it!