I’ve been getting quite addicted to this lately. Basically it’s a new thing from Google (labeled Beta as everything by Google ;)) and it puts you and another person together to label random images so they can improve the quality of tehir picture searches. Both you and your partner have 90 seconds to match the same image. So for example if there is the picture of a couple walking along a river it could be anything from man, woman, couple, river, green, blue, water, sky, couple, happy, etc.
Give it a go, but don’t blame me if you’re getting addicted! :)