Revit API 2013 training labs material has been updated and is available for download from the public Autodesk Developer Network site. You can find it under "Samples and Documentation" section:
For your convenience, I have also add the direct link here.
This is the materials that we use for classroom trainings. If you know the basic of .NET programming and are interested in learning Revit API, this will be a good starting point. I hope you will find it useful.