Microsoft Research has launched a new online game “Page Hunt,” you're shown a web page, which you’ve to ‘hunt down' using queries sent to Bing. When you see the web page, think of a set of terms that can get back this page. You type these words  into a search box. Page Hunt shows the top 5 results for this query from Bing. You get points if the web page you're 'hunting' is one of these top 5 result pages: 100 points if it's at position 1, 90 points at position 2 etc. If you don’t get it right, change the query and try hunting again. If you get it right, you advance to the next page. 

More info: Page Hunt