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Google has officially launched their structured data codelab, which allows you to walk through a step-by-step process to make your own structured data for your web site. Google's codelab walks you through adding several types of structured data to a simple HTML site, including where to place structured data on a site and how to validate it.
Aaron Bradley first posted about it on Twitter saying it was live since last month but now Google officially added a link to it from the main structured data developer pages on the left side bar.
When you click into it, you go to this section that says it takes about 30 minutes to go through the process. Here is a screen shot of this page:
Forum discussion at Twitter.
