Luis Fraguada and O'Reilly Media has published a series of training videos, Visual Programming in Rhino3D with Grasshopper.
Luis is a busy professional. At McNeel Europe he is a Rhino developer and an authorized trainer. Also, he is the Research Director for Built by Associate Data, an international design and architectural practice in Barcelona, and an instructor at the Institute for Advanced Architecture of Catalonia. He has even designed a custom 3D food printer.
For architects and designers who work with complex shapes and surfaces, Grasshopper is a visual programming tool to create rules and parameters that can be easily changed and updated.
You can check out several of the training videos for free. Try them ....