Microsoft Advertising is launching their promotion extensions in time for Christmas. The promotion extension can help your text ads stand out from other advertisers.
They allow you to highlight a special offer you have available, and they can be tied to different holidays and occasions. These extensions can be customised by occasion, promotion type, promotion details and start and end dates.
These extensions are currently only available to deliver in the United States, however their help page states they will be coming soon to other locations.