The latest in the series of strange Google Adsense ads is users reporting seeing the Google Checkout icons on Google Adsense ads. SEO Roundtable points out to a discussion going on at Digital Point forums where one member saw a Google Checkout icon on AdSense ads. They say you see a little shopping cart icon when you search at Google and the sponsored listings are from a site that accepts Google Checkout.
Other strange adsense ads people have spotted are Google graphical logos, Ad Links & Text Ad Units Combined, with favicons, with no “ads by google”, ads without titles and in multiple languages.