I'm trying to come up with a design for an image voting site that turns the (potentially boring) task of voting on thousands of images into a game. The goal is to get the user to vote on as many image pairs as possible without them getting bored.
My first thought was to use to the different ip addresses of uploaded images and turn the voting into a world journey for the user. The site opens on a world map and is presented a series of image "battles" where they have to choose the winning image out of the pair. Each world region will have anywhere from 10-100 image pairs that the user will vote on. As they complete the image pairs for a region, they are "flown" to another part of the world to keep the game going.

The goal of the world map approach is to collect the user's opinion on as many image pairs as possible while giving them the sense of: 1- accomplishment (finishing the image pairs of a region) 2- going around the world
I unfortunately ran into a subtle flaw of this approach: Image pair voting will be restricted to particular region...so you can never have an image pair composed of an image from japan against an image from the US.
I was wondering how I could adapt this approach to fix this flaw - ie allow image pairs to be composed of images from all over the world instead of a particular region only?
Or even if you could come with a different design that accomplishes the same goals (collect as many votes as possible while keeping the user motivated and not bored)
Thanks for your time