This rhino tutorial strive to teach you how to accurately construct a rim using NURBS. The tutorial is available for free, and is in QuickTime video format.
A video lesson from Rhino3D.TV give an insight into how to create a hair dryer where form is powered by a feature in Grasshopper module. Read more.
I try to watch through the former link but in vain. Log into Rhino3D.tv, you can download the zip file and watch the tutorial under the Grasshopper Categories. It’s Ok.