Google has been lately giving a lot of importance to rich snippets in search results. Data Highlighter is a point-and-click tool that can be used by anyone authorized for your site in Google Webmaster Tools. No changes to HTML code are required.
Instead, you just use your mouse to highlight and “tag” each key piece of data on a typical event page of your website.
To get started with Data Highlighter, visit Webmaster Tools, select your site, click the “Optimization” link in the left sidebar, and click “Data Highlighter”.
As of now it’s available in English only and for structured data about events, such as concerts, sporting events, exhibitions, shows, and festivals.