Google is testing new ad format, called Gadget Ads. Gadgets Ads are mini sites based on HTML and Flash. The new ad format will provide a new dynamic way for interacting with the consumers and more clicks for AdSense users 
. Gadget ads are like Mini Sites running on a web page. However there is no guarantee that the ads will appear on your site, but you may increase the chance by opting for rectangle, leaderboard, and skyscraper ads in the image only format.