I just noticed that MSDN posted a ton of SharePoint 2013 code samples on their site… you can find them here: http://code.msdn.microsoft.com/officeapps
I contributed a few to this list, specifically around SharePoint 2013 Windows Azure Workflow:
- SharePoint 2013 workflow: Call an External Web Service: this one shows how to create a workflow in Visual Studio 2012 that calls a web service using the new HTTP activities and the DynamicValue data type.
- SharePoint 2013 workflow: Create a Custom Action: this is the same thing as above, but I moved the web service call to a custom action for use in SharePoint Designer 2013 or Visual Studio 2012 workflows.